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Chirurgia spinală minim invazivă
Chirurgia spinală minim invazivă oferă pacienților oportunitatea unui tratament eficient, permițându-le o recuperare ultra rapidă și nu în ultimul rând minimizând leziunile induse chirurgical. Echipa noastră utilizează un spectru larg de tehnici minim invazive, din care enumerăm câteva: endoscopia cu variantele ei (transnazală, transtoracică, transmusculară, etc), microscopul operator, abordurile trans tubulare și nu în ultimul rând infiltrațiile la toate nivelurile coloanei vertebrale. www.neurohope.ro |
Despre miturile alimentare moderne(carbohidratii ingrasa, fructoza ingrasa si e toxica, glutenul e toxic, cerealele ingrasa si sunt nesanatoase).
1 votes
Last Updated: Oct 13 2019 20:47, Started by
skeptikal
, Dec 15 2014 01:14
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#37
Posted 13 January 2015 - 18:15
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Nu ma asteptam ca RO sa ocupe o pozitie atat de  La asta
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#38
Posted 20 January 2015 - 16:17
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Am ramas dator cu clarificarea ipotezei conform careia, in Paleolitic stramosii nostri au avut o dieta high fat. Aceasta idee reprezinta o dogma in cea mai mare parte a comunitatii low carb, paleo (cel putin in cazul acelora conduse de diversi guru autoproclamati experti "paleo"). Conform acestei dogme stramosii nostri aveau o dieta compusa din 60-70% grasimi (majoritatea saturate), 20-25% proteine si 5-20% carbohidrati. Cam acestea sunt procentele in jurul carora se invart cele mai multe diete recomandate ca fiind paleo. Se afirma chiar ca aceasta dieta ancestrala ar fi cetogenica si ca cetonele ar fi fost combustibilul primordial al stramosilor nostri pana in neolitic, cand aparitia agriculturii ar fi dus la inlocuirea cetonelor si acizilor grasi cu glucidele, ca sursa primara de energie.
M-am gandit sa prezint, in premiera pe acest forum, studiile stiintifice pe care se intemeiaza dieta paleo. In acest fel fiecare va putea judeca, in cunostiinta de cauza, cum stau lucrurile cu aceasta dieta. La originea dietei paleo sta un studiu din 1985 publicat de 2 antropologi, Boyd Eaton si Melvin Konner, in The New England Journal of Medicine, Paleolithic Nutrition - A Consideration of Its Nature and Current Implications . Acestia sunt considerati parintii dietei paleo. Desi publicat cu mult timp in urma, studiul nu a provocat nebunia la care asistam in prezent legat de dieta paleo. Avem acum carti despre dieta paleo The Paleo Diet , paleo pentru sportivi The Paleo Diet for Athletes , paleo pentru copii The Paleo Kid , paleo pentru femei Cavewomen Don't Get Fat , paleo pentru gravide The Paleo Diet For Pregnant Women And Babies , paleo pentru animale de companie Paleo Chef for Dogs: Homemade Gluten-Free Dog Food Recipes , cosmetice paleo Primal Colors Dark Warm Foundation , ciocolata paleo Caveman Bar Dark Chocolate , prajituri paleo Paleo Brownies , suplimente paleo Paleo Protein Supplement , cereale paleo?! On The Go Paleo Hot Cereal , paine paleo Paleo Bread , faina paleo Paleo Chocolate Cake and Muffin Mix , pizza paleo Paleo Pizza Cookbook , pana si bucataria italieneasca e paleo Italian Paleo , tricouri paleo Paleo T-shirts Aceasta nebunie este de data mult mai recenta, practic cam de 5 ani, paleo a inceput sa iasa din anonimat si sa devina mainstream. Acest studiu este pomenit pe diversele bloguri, in carti, articole, in sprijinul si justificarea acestei diete, este baza sa stiintifica. Dar oare ce ne dezvaluie acest studiu despre dieta ancestrala a stramosilor nostri? Inainte de a trece la discutarea studiului trebuie sa precizez ca el a suferit 2 revizii, una in 1997 si ultima in 2010, in care s-au actualizat informatiile. Ideile centrale si trendul general al articolului nu s-au schimbat semnificativ insa. Ideea de inceput este ca noi am evoluat astfel incat suntem adaptati la o dieta omnivora, caracterizata de flexibilitate in raport de locatia geografica, anotimpuri sau perioada paleontologica in care am evoluat. Insa timpul scurt scurs de la adoptarea agriculturii nu ne-a permis sa devenim adaptati la alimentele de baza existente in neolitic. "Bolile civilizatiei" sunt, asadar, rezultatul acestei neadaptari genetice. Quote HUMANITY has existed as a genus for about 2 million years, and our prehuman hominid ancestors, the australopithecines, appeared at least 4 million years ago. This phase of evolutionary history made definitive contributions to our current genetic composition, partly in response to dietary influences at that time. The foods available to evolving hominids varied widely according to the paleontological period, geographical location, and seasonal conditions, so that our ancestral line maintained the versatility of the omnivore that typifies most primates. Natural selection has provided us with nutritional adaptability. The human genetic constitution has changed relatively little since the appearance of truly modern human beings, Homo sapiens sapiens, about 40,000 years ago. Even the development of agriculture 10,000 years ago has apparently had a minimal influence on our genes. Certain hemoglobinopathies and retention of intestinal lactase into adulthood are “recent” genetic evolutionary trends, but very few other examples are known. Such developments as the Industrial Revolution, agribusiness, and modern food-processing techniques have occurred too recently to have had any evolutionary effect at all. Interesanta totusi precizarea facuta de cecetatori, si anume aceea ca aceste boli isi au originea in ultima suta de ani (secolul xx). De ce n-au aparut in toata istoria noastra de la inceputul agriculturii si pana acum? Quote Physicians and nutritionists are increasingly convinced that the dietary habits adopted by Western society over the past 100 years make an important etiologic contribution to coronary heart disease, hypertension, diabetes, and some types of cancer. These conditions have emerged as dominant health problems only in the past century and are virtually unknown among the few surviving hunter-gatherer populations whose way of life and eating habits most closely resemble those of preagricultural human beings. Urmeaza o trecere in revista a evolutiei dietei de-a lungul timpului. Quote The ancestral mammals were insectivores, and invertebrate predation was thus the basis from which primate feeding behavior evolved. However, as the primate order expanded and body size increased, vegetable foods became increasingly important for most species. During the Miocene era (from about 24 to about 5 million years ago) fruits appear to have been the main dietary constituent for hominids, but their fossilized dental remains seem suitable for mastication of both animal and vegetable material. After the divergence of the human and ape lines (now thought to have occurred between 7.5 and 4.5 million years ago) our ancestral feeding pattern included increasing amounts of meat, although it is uncertain whether this change reflects hunting, scavenging, or both. It is now thought that Hamo habilis began to manufacture stone tools about 2 million years ago and that the succeeding species, Homo erectus, began to consume a much larger amount of meat between 1.8 and 1.6 million years ago. It is clear that thereafter early human beings consumed a considerable amount of meat: large accumulations of animal remains are found where they lived, the tools they used were mainly geared toward processing game, and their living sites were selectively located in areas where there was a relatively substantial biomass of large grazing animals. Dupa cum se observa, fructele (deci carbohidrati, deci fructoza) au constituit o perioada indelungata sursa principala de hrana si au modificat genomul in consecinta, asta apropo de ingrijorarea unora care-si limiteaza consumul de fructe din diverse motive inchipuite. Exista o asimetrie intre urmele lasate de consumul de carne (oase, unelte) si urmele lasate de consumul de produse vegetale (perisabilitatea acestora nu permite supravietuirea multor dovezi), ceaa ce face ca uneori sa se supraestimeze consumul de carne. Consumul de peste si produse asociate este de natura recenta. Quote The importance of vegetable foods is harder to assess, since plant remains are poorly preserved. Fossilized fruit pits and nuts are commonly found, but tools for processing plant foods are conspicuously absent in comparison with their widespread proliferation in later prehistory. Shells and fish bones are unknown in archaeological material dating from before 130,000 years agon and are found infrequently in material dating from before 20,000 years ago, so that, in paleontological terms, widespread use of aquatic foods is a recent phenomenon. Dieta este compusa 50% produse de origine animala si 50% produse vegetale. Quote Several authorities have estimated that Homo erectus and early Home sapiens obtained over 50 per cent of their diet from plant sources.However, when the Cro-Magnons and other truly modern human beings appeared, concentration on big-game hunting increased. In some areas during this time meat probably provided over 50 percent of the diet. But because of overhunting, climate changes, and population growth, the period shortly before the inception of agriculture and animal husbandry was marked by a shift away from biggame hunting and toward a broader spectrum of subsistence activities. Aparitia agriculturii a dus la o scadere in inaltime, o constitutie mai firava, (din cauza dietei mai sarace in proteine), o serie de boli infectioase (din cauza colectivitatilor umane si apropierii de animale). Insa in pe parcurs dieta s-a imbunatatit si diferentele s-au recuperat. Quote Agriculture markedly altered human nutritional patterns: over the course of a few millenia the proportion of meat declined drastically while vegetable foods came to make up as much as 90 per cent of the diet. This shift had prominent morphologic consequences: early European Homo sapiens sapiens, who enjoyed an abundance of animal protein 30,000 years ago, were an average of six inches taller than their descendants who lived after the development of farming. The same pattern was repeated later in the New World: the Paleoindians were big-game hunters 10,000 years ago, but their descendants in the period just before European contact practiced intensive food production, ate little meat, were considerably shorter, and had skeletal manifestations of suboptimal nutrition, which apparently reflect both the direct effects of protein-calorie deficiency and the synergistic interaction between malnutrition and infection. Since the Industrial Revolution, the animal-protein content of Western diets has become more nearly adequate, as indicated by increased average height: we are now nearly as tall as were the first biologically modern human beings. However, our diets still differ markedly from theirs, and these differences lie at the heart of what has been termed “affluent malnutrition" Acum studiul incearca sa determine in termeni mai precisi compozitia dietei omului preistoric, studiind 50 de populatii primitive de vanatori-culegatori care au supravietuit pana in zilele noastre. Se observa diversitate, nu exista o singura dieta sau un singur tipar al macronutrientilor. Quote Over 50 hunter-gatherer societies have been studied extensively enough tojustify some nutritional generalizations about them. In general, groups of hunter-gatherers who, like the earliest human beings, live in an inland, semitropical habitat derive between 50 and 80 per cent of their food (by weight) from plants, with animal sources providing between 20 and 50 per cent.“ Coastal and riverine peoples derive from 10 to 50 per cent of their food from fishing; for example, the Australian Aborigines of Arnhem Land get about 40 per cent of their total intake from fish and shellfish, whereas only a quarter comes from plants. Because oftheir harsh environment, Arctic hunters, such as the aboriginal Eskimos, obtain less than 10 per cent of their food from vegetation. Carnea. Carcasa vanatului are aprox. 4% grasime, fata de 25-30% cat are carcasa unui animal crescut in captivitate. Carnea vanatului are de 5x mai multe grasimi polinesaturate (PUFA) per gram decat carnea din supermarket. Continutul in EPA este mai mare. Colesterolul si structura aminoacizilor nu difera. Canea vanatului este mai saraca in calorii. Quote Modem high-fat carcasses are 25 to 30 per cent fat or even more. In contrast, a survey of 15 different species of free-living African herbivores revealed a mean carcass fat content of only 3.9 per cent. Not only is there more fat in domesticated animals, its composition is different; wild game contains over five times more polyunsaturated fat per gram than is found in domestic livestock. Furthermore, the fat of wild animals contains an appreciable amount (approximately 4 %) of eicosapentaenoic acid (C2O:5), a long-chain, polyunsaturated, w3 fatty acid currently under investigation because of its apparent antiatherosclerotic properties. Domestic beef contains almost undetectable amounts of this nutrient. Meat from free-living animals has fewer calories and more protein per unit of weight than meat from domesticated animals, but the amino acid composition ofmuscle tissue from each source is similar? Since the cholesterol content of fat is roughly equivalent to that of lean tissue,“ the cholesterol content of game would not be expected to differ substantially from that of commercially available meat. Produse vegetale. Se consuma intr-o mai mare diversitate decat populatiile agricole, fructe, radacini, leguminoase, nuci, tuberculi, cantitati mici de cereale. Quote Except for Eskimos and other high-latitude peoples, hunter-gatherers typically use many species of wild plants for food. Roots, beans, nuts, tubers, and fruits are the most common major dietary constituents, but others, ranging from flowers to edible gums, are occasionally consumed. Small cereal grains, which have been staples for “civilized” peoples since the Agricultural Revolution, make a surprisingly minor contribution overall; however, the wide range of vegetable foods eaten by foragers contrasts with the relatively narrow variety of crops produced by horticulturists and traditional agriculturists. Dieta era foarte bogata in proteine in jur se 250g/zi, slaba in grasimi in jur de 70g/zi, moderata (dupa standardele de azi) in carbohidrati 333g/zi, bogata in fibre 40g/zi. . Ca si energie proteinele contribuie intre 25-60% din energie, glucidele 14-55% si lipidele 20-25%, raportul intre PUFA/SFA era de 1.4 
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14 downloadsAportul de calciu, vitamina C, potasiu, colesterol era mai mare decat in zilele noastre. Prin urmare dieta paleolitica NU ERA BOGATA DE GRASIMI SI NICI IN GRASIMI SATURATE. ERA BOGATA IN PROTEINE. SI AVEA CANTITATI APRECIABILE DE CARBOHIDRATI. Quote In the hunting society of our ancestors meat provided a large fraction of each day’s food, ensuring high iron and folate levels. Protein contributed twice to nearly five times the proportion of total calories that it does for Americans. Their high-meat diet contained a high level of cholesterol — similar to or even higher than the level in our diet; most paleolithic human beings must have greatly exceeded the U.S. Senate Select Committee’s recommended cholesterol level. Conversely, they ate much less fat than we do, and the fat they ate was substantially different from ours. Whether subsistence was based predominantly on meat or on vegetable foods, the paleolithic diet had less total fat, more essential fatty acids, and a much higher ratio of polyunsaturated to saturated fats than ours does. In comparison with us, our paleolithic ancestors consumed more structural and less depot fat. Ultimately, of course, only experimental and clinical studies can confirm hypotheses about the medical consequences of dietary choices. Nevertheless, it is both intellectually satisfying and heuristically valuable to estimate the typical diet that human beings were adapted to consume during the long course of our evolution. Points of convergence between this estimate and modern recommendations are encouraging, and points of divergence suggest new lines ofresearch. The diet ot-our remote ancestors maybe a reference standard for modern human nutrition and a model for defense against certain “diseases of civilization.“ In concluzie, dieta paleolitica nu continea nici unt, nici untura, nici ulei de cocos, nici carne grasa (exceptie organele), nici smantana grasa. Acest tip de dieta este o creatie fantezista a diversilor "guru" care vand iluzii ignorantilor. Cine se apuca sa citeasca literatura in domeniu ramane surprins de contrastul dintre realitatea acestor studii si "realitatea" diverselor carti de popularizare. Nu veti regasi aversiunea fata de carbohidrati, prezenta la majoritatea adeptilor "paleo", nu veti regasi sanctificarea grasimii. Veti gasi doar concluzii desprinse din realitatea datelor si nu din iluzia unor fantasme: dieta continea mai putine glucide decat dietele contemporane, erau glucide complexe, foarte multe fibre (deseori ignorate, considerate inutile sau chiar daunatoare de multi adepti paleo), multe proteine, grasimi putine si majoritar PUFA, multe fructe, consumul de produse lactate era practic zero, pana si cerealele salbatice erau prezente intr-o masura mica in dieta. Ceea ce se prezinta mainstream ca fiind paleo este o nascocire comerciala venita mai ales pe filiera Atkins/Taubes. Edited by skeptikal, 20 January 2015 - 16:42. |
#39
Posted 20 January 2015 - 17:00
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Io de la bun inceput dieta paleo am inteles-o exact cum este descrisa pe pagina de wikipedia
The diet Major advocates of the diet believe that this includes eating:[12] Seeds such as walnuts are rich sources of protein and micronutrients More protein and meat: Meat, seafood, and other animal products represent the staple foods of modern-day Paleo diets, since advocates claim protein comprises 19-35% of the calories in hunter-gatherer diets.[13] The Centers for Disease Control and Prevention, the national public health institute of the United States, recommends that 10-35% of calories come from protein.[14] Advocates recommend, relative to modern diets, that the Paleolithic diet have moderate to higher fat intake dominated by monounsaturated and polyunsaturated fats and omega-3 fats, but avoiding trans fats, and omega-6 fats. Fewer carbohydrates: Non-starchy vegetables. The diet recommends the consumption of non-starchy fresh fruits and vegetables to provide 35-45 % daily calories and be the main source of carbohydrates.[13] According to the United States Department of Agriculture, the acceptable macronutrient distribution range for carbohydrates is 45 to 65 percent of total calories.[15] A typical modern diet gets a lot of carbohydrates from dairy products and grains, but these are excluded in the Paleolithic diet. High fiber: High fiber intake not via grains, but via non-starchy vegetables and fruits.[13] Exclusions Food groups that advocates claim were rarely or never consumed by humans before the Neolithic agricultural revolution are excluded from the diet. These include: dairy products grains, for example wheat, rye, canary seed, and barley, which make it a gluten-free diet legumes, for example beans and peanuts processed oils refined sugar salt Neither alcohol[16] nor coffee is considered "paleo" as our ancestors could not produce these drinks. Edited by Handicarpati, 20 January 2015 - 17:04. |
#40
Posted 24 January 2015 - 15:34
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Al doilea studiu care a furnizat date cantitative despre dieta paleolitica este Plant-animal subsistence ratios and macronutrient energy estimations in worldwide hunter-gatherer diets Printre autori este si Boyd Eaton care a contribuit si la geneza studiului din 1985. Studiul aduce o serie de ajustari celui precedent si modifica intr-o maniera considerabila structura macronutrientilor, astfel incat unele diete paleolitice pot fi considerate high fat. Din aceasta cauza este studiul cel mai des citat in comunitatea paleo, insa cu omisiuni importante care-i schimba pur si simplu sensul asa cum a fost el definit de cercetatori.
Studiul incepe cu precizarea neajunsurilor studiului precedent: primul studiu n-a inclus in categoria produselor de origine animala si cele obtinute prin pescuit. Quote The reconstruction of preagricultural human diets by using indirect procedures has only recently been attempted. In their seminal paper, Eaton and Konner estimated the dietary macronutrient and trace nutrient contents of Paleolithic humans. These authors estimated the projected average dietary macronutrient composition (as % of energy) to be 21% fat, 34% protein, and 45% carbohydrate, which was recently updated to 22% fat, 37% protein, and 41% carbohydrate. Implicit in Eaton et al’s estimation of representative, or average, Paleolithic diets was an assumed ratio of plant to animal (P:A) energy subsistence of 65:35, which was based on Lee’s compilation of selected hunter-gatherer subsistence data taken from the Ethnographic Atlas, an ethnographic compendium of 862 of the world’s societies. Because Lee did not sum animal foods derived from hunting and animal foods derived from fishing, P-A subsistence ratios of worldwide hunter-gatherers are not reported in Lee’s analysis. Furthermore, the subsistence data from the Ethnographic Atlas are not reported as percentages of energy, but simply as a percentage of the subsistence economy. Eaton and Konner’s model for projected Paleolithic diets accommodates P-A energy subsistence ratios other than 65:35, and these authors suggested that many macronutrient combinations are possible. Many other researchers indicated that the average hunter-gatherer subsistence pattern would have included more animal food than the 35% of energy originally estimated by Eaton et al. We analyzed the economic subsistence data for all 229 hunter-gatherer societies using all 3 subsistence categories (gathered plant foods, hunted animal foods, and fished animal foods) contained within the updated and revised version of the Ethnographic Atlas. In continuare se precizeaza ce modifucari sunt aduse in acest studiu: se ia in calcul, la stabilirea macronutrientilor, carcasa intregului animal, se iau in considerare diferite procente de grasime ale animalelor (in functie de anotimp), includerea mai multor populatii de vanatori culegatori. Quote In the present model, we used the same general approach that Eaton et al. used, except that we made several important revisions. We 1) added estimations of macronutrient energy for multiple P-A subsistence ratios representing most hunter-gatherer societies in the larger, revised Atlas; 2) incorporated both hunted and fished animal foods in the animal portion of the P-A subsistence ratio; 3) included various percentages of body fat of animals in the animal portion of the P-A subsistence ratio; and 4) refined estimates of the amounts of energy from protein and fat in animal-based foods to reflect not merely mean energy values, but the cubic relations among these variables and percentage body fat (by wt). Previous models of reconstructed preagricultural diets have assumed that muscle tissue was the sole animal tissue consumed; however, many ethnographic reports of various hunter-gatherer societies showed that virtually all of the edible carcass was consumed. Rezultate: - peste 70% din populatii isi obtin peste 50% din energie din produse de origine animala - 13% din populatii isi obtin peste 50% din energie din produse vegetale - 58% din populatiile cercetate isi obtin peste 66% din energie din produse de origine animala - 4% din populatii isi obtin peste 66% din energie din produse vegetale - 20% din populatii depind intr-o foarte mare masura (86-100%) de produse de origine animala - nici o populatie nu depinde intr-o foarte mare masura (86-100%) de produse vegetale - nu s-au identificat populatii strict vegetariene Quote In the present model, we did not use a single P-A energy subsistence ratio but rather a series of P-A energy subsistence ratios (35:65, 45:55, 50:50, 55:45, and 65:35) that fall within the range of most (58%; n = 132) of the hunter-gatherer societies considered in this analysis. Within each of these categories, we calculated the overall dietary macronutrient energy ratio for 5 different whole-body fat percentages in both fish and mammalian prey species (2.5%, 5%, 10%, 15%, and 20%). Most (73%) of the worldwide hunter-gatherers derived >50% (≥56–65%) of their subsistence from animal foods (hunted and fished), whereas only 13.5% of worldwide hunter-gatherers derived >50% (≥56–65%) of their subsistence from gathered plant foods. Of the 229 hunter-gatherer societies listed in the Ethnographic Atlas, 58% (n = 133) obtained ≥66% of their subsistence from animal foods in contrast with 4% (n = 8) of societies that obtain ≥66% of their subsistence from gathered plant foods. No hunter-gatherer population is entirely or largely dependent (86–100% subsistence) on gathered plant foods, whereas 20% (n = 46) are highly or solely dependent (86–100%) on fished and hunted animal foods. S-a identificat un tipar al contributiei macronutrientilor in functie de latitudine. La peste 40 grade latitudine nordica sau sudica creste ponderea produselor de origine animala. Vanatul ramane constant, insa creste ponderea produseler din pescuit si scade ponderea celor vegetale. (Africa unde am evoluat cea mai mare parte a timpului se afla sub 40 grade latitudine). De asemenea nu exista o singura dieta caracteristica, ci o multitudine in functie de disponibilitatea resurselor. Quote The subsistence dependence on combined hunted and fished animal foods is constant in hunter-gatherer societies living at low-to-moderate latitudes (0–40 N or S) and the median value falls within the 46–55% subsistence class interval. For societies living at >40 N or S, there is an increasing latitudinal dependence on animal foods, which is primarily met by more fished animal foods. Significant relations exist between latitude and subsistence dependence on gathered plant foods (r = 20.77, P < 0.001) and fished animal foods (r = 0.58, P < 0.001), whereas no significant relation exists between latitude and subsistence dependence on hunted animal foods (r = 0.08, P = 0.23). Our data clearly indicate that there was no single diet that represented all hunter-gatherer societies. However, there were dietary trends that transcend geographic and ecologic boundaries and represent nearly all the world’s hunter-gatherers. These nutritional trends, when analyzed under the scrutiny of modern nutritional theory, may have important implications for the mediation of nutritionally related, chronic diseases of Westernized societies. Conform datelor consumul de proteine era foarte ridicat, in fapt atat de ridicat incat s-a pus problema ca nu era fiziologic posibil, prin urmare trebuie sa fi existat diverse strategii de limitare a consumului de proteine, fie prin cresterea consumului de carbohidrati, fie prin cresterea consumului de grasime (aceasta din urma pare sa fi fost preferata). Quote Dietary protein was estimated to have comprised between 19% and 50% of total energy intake, depending on the P-A subsistence ratio and the percentage body fat by weight in the prey animals. However, humans may not tolerate diets that contain >35–40% protein by energy. Excess consumption of dietary protein from the lean meats of wild animals leads to a condition referred to by early American explorers as “rabbit starvation,” which initially results in nausea, then diarrhea, and then death. Clinical documentation of this syndrome is virtually nonexistent, except for a single case study. Despite the paucity of clinical data, it is quite likely that the symptoms of rabbit starvation result primarily from the finite ability of the liver to up-regulate enzymes necessary for urea synthesis in the face of increasing dietary protein intake. To circumvent the dietary protein ceiling, hunter-gatherers generally would have had several options. They could have 1) increased their P-A energy subsistence ratios by eating more plant-food energy; 2) hunted larger animals because percentage body fat increases with increasing body size; 3) hunted smaller animals during the season in which body fat is maximized; 4) selectively eaten only the fattier portions of the carcass, including lipids boiled from the cancellous tissues of bones, and discarded the rest; 5) increased their intake of concentrated sources of carbohydrate such as honey; or 6) implemented ≥2 of the 5 options. The solution preferred by most worldwide hunter-gatherers to circumvent excess dietary protein would likely have been a relative increase in total dietary fat from animal foods. Of the options available to achieve this goal, the selective consumption of fatty portions of the carcass while discarding leaner portions of the carcass would have been quite costly on the basis of the ratio of energy capture to energy expenditure.The selection of larger prey species, when ecologically and technologically possible, may have been the preferred option. Datele arata ca in functie de latitudine ponderea macronutrientilor variaza destul de mult: proteine 19-35%, carbohidrati 22-40%, grasimi 28-58%. Acest din urma procent este cel care face ca studiul sa fie preferratul comunitatii paleo, insa se ignora mai multe lucruri: exista o variatie, nu este un procent fix, este specific latitudinilor inalte (peste 40 grade N sau S), insa noi am evoluat cea mai mare parte in Africa care se afla intre 30 grade N si S, Grasimile erau in cea mai mare parte nesaturate, carbohidratii ajungeau pana la 40%, erau foarte multe proteine, nu era o dieta cetogenica. Quote For worldwide hunter-gatherers, the most plausible (values not exceeding the mean MRUS) percentages of total energy from the macronutrients would be 19–35% for protein, 22–40% for carbohydrate, and 28–58% for fat. Because our sample contained more societies (n = 133) located above 40 N or S latitude than below it (n = 96) and because there was a substantial increase in combined (hunted and fished) animal-food subsistence dependence at the expense of plant foods in those living above 40 N or S latitude, the median value for animal-food subsistence was positively skewed. With use of a more conservative subsistence dependence on animal foods (hunted +fished) of 50%, a value that falls within the median class interval (46–55%) for animal-food subsistence values for hunter-gatherer societies living from 0 to 40 N or S latitude , the projected ranges of percentages of total energy (not exceeding the mean MRUS) would be 20–31% for dietary protein, 31% for carbohydrate, and 38–49% for fat. Limitarile studiului: - cercetotorii admit ca datele din Atlasul Etnografic (sursa informatiilor) nu sunt precise, ci mai degraba estimari - aproape 60% din esantion este compus din populatii care traiesc la latitudini peste 40 grade, deci cu consum mai mare de produse de origine animala - estimarea consumului de plante s-a facut pe baza unui esantion specific aborigenilor din Australia care a fost extins la intregul esantion de populatii - s-a estimat un consum constant de 35% de produse de origine animala la intreg esantionul de populatii, insa cercetotorii recunosc ca exista populatii care nu pescuiesc si prin urmare au o pondere mai mica a acestui tip de produse - s-a estimat un procent egal de grasime atat la animale cat si la pesti, desi acesta supozitie s-ar putea sa nu fie corecta Quote In the present model, we used a fixed plant-food macronutrient value of 62% of energy from carbohydrate, 24% from fat, and 14% from protein, derived entirely from Australian Aboriginal plant foods. Plant-food types in hunter-gatherer diets obviously vary by season, latitude, and geographic locale; consequently, variations in plant-food macronutrient composition by plant type will influence the overall estimated dietary macronutrient energy values. Despite these potential confounders, previous estimates of the percentages of energy derived from plant-food macronutrients in preagricultural human diets were 68% of energy from carbohydrate, 19% from fat, and 13% from protein, which are similar to the values we derived. For our analysis, we also assumed a constant hunted animal-food intake (35% of energy) that was based on previous estimates and the present ethnographic data. Certainly, there are small numbers of hunter-gatherer populations, such as nonfishing societies, who do not necessarily conform to this assumption. Within animal-food (fished + hunted foods) subsistence dependence, we assumed the same percentages of body fat for both hunted and fished animals; however, these values may not be linked. Obviously, these and other variables not factored into the model can subtly and occasionally overtly influence the outcome of our projected estimates. Perhaps the most important variable influencing the estimation of the dietary macronutrient ratio in hunter-gatherer populations, when indirect procedures are used, is the validity of ethnographic data. Other ethnographers who compiled hunter-gatherer data from the Ethnographic Atlas noted that the scores Murdock assigned to the 5 basic subsistence economies are not precise, but rather are approximation generally based on raw weights of the dietary items. Although estimations of energy by weight of wild plant and animal foods may sometimes yield results similar to actual values, there is considerable room for error. In incheiere autorii mentioneaza ca, desi consumul de grasimi in cazul unor populatii de vanatori-culegatori depaseste cantitatea maxima recomandata in zilele noastre, tipul de grasimi consumat de aceste populatii difera de tipul de grasimi incriminate astazi (grasimile saturate). Quote The range of percentages of energy for carbohydrate and protein in the diets of most hunter-gatherer societies worldwide falls outside the average value found in Western diets and in recommended healthy diets [15% of energy from protein, 55% from carbohydrate, and 30% from fat]. Our macronutrient projections for worldwide hunter-gatherer diets indicate that these diets would be extremely high in protein (19–35% of energy) and low in carbohydrate (22–40% of energy) by normal Western standards, whereas the fat intake would be comparable or higher (28–58% of energy) than values currently consumed in modern, industrialized societies. However, the types and balance of fats in hunter-gatherer diets would likely have been considerably different from those found in typical Western diets. Cereal grains represent the highest single food item consumed on the basis of energy content in both the United States and the rest of the world; however, they were rarely consumed by most hunter-gatherers , except as starvation foods or by hunter-gatherers living in arid and marginal environments. Cum autorii nu fac precizari mai precise in legatura cu tipul grasimilor in acest studiu, am gasit un alt studiu al lui Cordain in care se fac precizari suplimentare Saturated Fat Consumption in Ancestral Human Diets Quote In the typical hunter-gatherer diet, the animal subsistence falls between 55 to 65% of total energy; consequently, in this group, the mean dietary saturated fat as a percentage of total energy is higher still (15.1 + 1.9). Even in plant dominated (>50% energy from plant foods) hunter-gatherer diets, the mean dietary saturated fat as a percentage of total energy is slightly higher (11.3 + 2.8) than recommended healthful values of <10%. The present data suggests that the normal dietary intake of saturated fatty acids that conditioned our species genome likely fell between 10 to 15% of total energy, and that values lower than 10% or higher than 15% would have been the exception rather than the rule. Consequently, population-wide recommendations to lower dietary saturated fat below 10% to reduce the risk of CAD have little or no evolutionary foundation in pre-agricultural Homo sapiens. Because no randomized clinical trials of low saturated fat diets of sufficient duration have been carried out, there is a lack of knowledge how low saturated fat intake can be without the risk of potentially deleterious health consequences. Hence, extremely low, or conversely, high, lifelong consumption of dietary saturated fatty acids is likely to be discordant with the human genome. Intr-adevar consumul de grasimi saturate in dietele paleolitice pare sa fie mai mare decat recomandarile oficiale din zilele noastre, de 10%, insa nu cu mult, intre1-5% maxim. Trebuie precizat ca recomandarile actuale au un caracter general si anumitor categorii (de exemplu sportivilor) li se permite o cantitate mai mare de grasimi saturate. Dar stramosii nostri aveau un nivel de activitate fizica mult superior oamenilor normali din prezent, asemanator mai degraba cu cel al sportivilor, din acest motiv acel consum mai mare de grasimi saturate nu este mare tinand cont de aceasta variabila. In nici un caz aceste procente ale macronutrientilor, asa cum reies ele din studiile stiintifice, nu seamana deloc cu fantasmagoricele diete paleo vandute de diversi "guru", gen 60-70% grasimi, majoritatea saturate, low carb, fara prea multe fructe (fructoza ingrasa?!), fara prea multe fibre. La nivelul fantezist de grasimi saturate propus de acestia, s-ar ajunge la un nivel de peste 30-35% pondere in dieta, nivel nesustinut de nici un studiu stiintific de pana in prezent. Dupa cum se remarca din ultima citare un nivel peste 15% grasimi saturate cel mai probabil nu este in corcondanta cu genomul uman, asa cum a rezultat el in urma evolutiei. La final va prezint concluziile autorilor asa cum reies ele din studiul Paleolithic nutrition what did our ancestors eat (dateaza din 2009, practic o sinteza a studiului din 2000, prezentat aici, dar intr-o forma mai usor accesibila) Quote Unfortunately, in the context of western diets, increasing meat consumption (particularly red and processed meat) is linked to a greater risk of cardiovascular disease. In countries like the USA, meats contribute much of the fat, and more importantly, about one third of the saturated fat, the kind mostly clearly linked to adverse outcomes. Thus, a high meat diet, regardless of its fat quantity and type, is generally perceived to be unhealthy and to promote cardiovascular and other chronic diseases. Yet Australian red meat derived from grazing animals is generally lean, low in saturated fat and contains significant amounts of healthy long chain omega-3 fats. Our research provides evidence that the animal foods that dominated hunter-gatherer diets were also low in saturated fat and high in good fats. This nutritional pattern would not have promoted atherosclerosis (hardening of the arteries) or chronic disease. There is now strong evidence that the absolute amount of dietary fat is less important in reducing the risk for cardiovascular disease than the type of fat. Fatty acids that increase blood cholesterol levels include lauric acid (C12:0), myristic acid (C14:0), palmitic acid (C16:0), and some trans fatty acids (Grundy, 1997), whereas monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids reduce cholesterol levels. Stearic acid (C18:0), the major fatty acid in chocolate and lean red meat is neutral. The high reliance on animal foods may not have elicited an adverse blood lipid profile because of the benefits of high dietary protein and low level of dietary carbohydrate. Although fat intake would have been similar to or higher than that found in western diets, there were important qualitative differences. The high levels of MUFA and PUFA and omega-3 fatty acids, would have served to inhibit the development of cardiovascular disease. Other dietary characteristics including high intakes of antioxidants, fibre, vitamins and phytochemicals along with a low salt intake may have operated synergistically with lifestyle characteristics (more exercise, less stress and no smoking) to further deter the development of disease. |
#41
Posted 24 January 2015 - 17:20
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O sa dau paste direct din The Paleo Diet v5.0 a lui Cordain
[ http://i61.tinypic.com/1zgq6vl.jpg - Pentru incarcare in pagina (embed) Click aici ] [ http://s29.postimg.org/maeu14nzb/Untitled2.jpg - Pentru incarcare in pagina (embed) Click aici ] [ http://s7.postimg.org/fjvqhznwr/Untitled.jpg - Pentru incarcare in pagina (embed) Click aici ] Edited by Handicarpati, 24 January 2015 - 17:25. |
#42
Posted 25 January 2015 - 18:45
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@Handicarpati Cordain este adeptul unei diete Paleo traditionale asa cum reiese din studiile publicate de el si de altii, insa el nu este singur pe "piata" promovarii acestor diete. Multi alti autori, deseori fara vreo pregatire stiintifica sau chiar cu studii unii dinttre ei, promoveaza un tip de diete care nu se potrivesc deloc cu cele din cercetarile stiintifice.
Majoritatea celor care au o dieta low carb sau care incearca o dieta paleo cred ca aceasta este bogata in grasimi saturate sau obligatoriu bogata in grasimi, insa din cercetari cu reiese ca macronutrientii variau destul de mult si autorii insista mai mult pe proteine, fibre, antioxidanti, grasimi nesaturate si niveluri mai degraba modeste de grasime saturata, nicidecum nivelurile uriase promovate de unii. Aceste diete par sa fie mai degraba dominate de carne, de proteine si nu exista aceasta reticente in privinta fibrelor sau a fructelor cum exista in recomandarile multor "guru". De altfel acesta este si motivul pentru care prezint aceste studii, astfel incat doritorii sa afle cum sunt aceste diete in realitate, asa cum reies ele din cercetarile in domeniu. Mai este si un alt palier al discutiei: sunt aceste diete (in formula lor originala nealtearata) pe deplin acceptate de comunitatea stiintifica? Raspunsul este ca mai degraba nu, desi este interes pentru ele si s-au facut cercetari experimentale cu aceste diete pentru a afla efectele fiziologice produse, lucru pe care o sa-l discut in postarile viitoare. Motivul pentru care nu sunt pe deplin acceptate este ca nu sunt multe experimente pana in prezent si au in general o durata mica de timp, pentru a se trage concluzii definitive. Un alt motiv este ca sunt dispute pe definitia si sensul real al acestei adaptari genetice la aceste diete si presupusa neadaptare la alimentele asa zis neolitice (cereale, legume, lactate). Studiul din 2000, din postarea anterioara a fost intampinat si cu critici din partea altor cercetatori. O asemenea opinie separata este si Hunter-gatherer diets - a different perspective O sa rezum principalele puncte de vedere. Un prim argument impotriva consumului mare de produse de origine animala este un studiu al lui Richard Lee (un antropolog, care in anii "70 a publicat o serie de lucrari referitoare la dietele populatiilor primitive), in care proportia in intre plante si produse de origine animala este de 65-35%. Apoi sunt aduse in discutie circumstantele in care datele din Atlasul Etnografic au fost culese. Practic acest atlas a fost intocmit pe parcursul primei jumatati sa sec. xx, deseori de cercetotori fara pregatire in nutritie. De asemenea multi dintre ei fiind barbati si crescuti in cultura de inceput de secol xx, probabil au acordat un rol mai putin semnificativ femeilor din populatiile cercetate, lucru de natura sa afecteze acuratetea datelor, avand in vedere ca femeile se preocupau mai ales cu culesul plantelor si fructelor. De asemenea se mentioneaza ca starea de sanatate era buna si in cadrul populatiilor care consumau mai multe produse vegetale decat cele de origine animala. Quote The hunter-gatherer data used by Cordain et al came from the Ethnographic Atlas, a cross-cultural index compiled largely from 20th century sources and written by ethnographers or others with disparate backgrounds, rarely interested in diet per se or trained in dietary collection techniques. Some societies coded as hunter-gatherers in the Atlas probably were not exclusively hunter-gatherers or were displaced agricultural peoples Because most of the ethnographers were male, they often did not associate with women, who typically collect and process plant resources. Data on modern-day hunter-gatherers as well as hunter-gatherer-agriculturalists who consumed traditional diets indicate that such societies are largely free of diseases of civilization regardless of whether a high percentage of dietary energy is supplied by wild animal foods (eg, in Canadian Eskimos), wild plant foods (eg, in the !Kung), or domesticated plant foods taken primarily from a single cultivar (eg, in the Yanomamo). Lee found that gathered vegetable foods were the primary source of subsistence for most of the hunter-gatherer societies he examined, whereas an emphasis on hunting occurred only in the highest latitudes. Apoi se contesta ideea ca suntem adaptati genetic la o dieta cu continut ridicat de carne, intrucat dovezile lipsesc. In afara situatiilor rare cand enzima sucraza lipseste la unii indivizi cu diete bogate in produse de origine animala, altele nu prea exista, ori o asemenea adaptare trebuie sa fi lasat urme. De asemenea ne separa diferente clare de carnivore care au asemenea adaptari precum imposibilitatea de a sintetiza vitamina A si B3 (carnivorele isi procura vitamina A si B3 obligat din carne), insa noi le putem obtine si din surse vegetale. Vitamina C o obtinem preponderent din produse vegetale. Carnivorele au un necesar mult mai mare de proteine decat oamenii. Quote Furthermore, although humans can thrive on a diversity of diets, we know of few specific genetic adaptations to diet in our species. Those few identified seem to be largely (although not exclusively) the result of regulatory mutations (eg, lactase synthesis in adulthood in some individuals) and unique selective pressures favoring such adaptations appear fairly well understood. Other than the occasional absence of intestinal sucrase, circumpolar peoples (or others with diets with a high animal food content) have not been shown to have special genetic adaptations that suit them for such diets In contrast, obligate carnivores, such as those of the cat family, show a range of specific metabolic adaptations to their all-flesh diets, including an unusually high requirement for protein for maintenance and growth, an unusual pattern of gluconeogenesis, and an inability to synthesize vitamin A and niacin from dietary precursors Modern human nutritional requirements (eg, the need for a dietary source of vitamin C), features of the modern human gut (haustrated colon), and the modern human pattern of digestive kinetics (similar to that of great apes) suggest an ancestral past in which tropical plant foods formed the basis of the daily diet, with perhaps some opportunistic intake of animal matter. Apoi se pune in discutie limita de 2.5 milioane de ani, de la care cercetotorii cred ca a inceput adaptarea la o dieta caracterizata de o preponderenta a produselor de origine animala. Se propune o limita de 25 de milioane de ani, de la aparitia primatelor antropoide caracterizate de o dieta frugivora care trebuisa fi lasat urme consistente in genomul uman datorta perioadei lungi (25 - 2.5 miioane de ani). Urmele arheologice, desi indica consumul de carne nu indica si proportia fata de produsele vegetale, lucru ingreunat si de perisabilitatea acestora din urma. Quote Food has played a major role in human evolution, but in a somewhat different manner than is generally appreciated. Humans are not self-made creations dietarily, but rather have an evolutionary history as anthropoid primates stretching back more than 25 million years, a history that shaped their nutrient requirements and digestive physiology well before they were humans or even protohumans. In hominoids, features such as nutrient requirements and digestive physiology appear to be genetically conservative and probably were little affected by the hunter-gatherer phase of human existence. Although most wild anthropoids eat little animal matter, its digestion, at least to some point, does not pose a problem. The barrier to greater meat eating in anthropoids appears to be the high cost of prey acquisition in the natural environment. If they could circumvent this cost routinely, many wild anthropoids would surely eat more animal foods. Archaeologic evidence shows that early humans did find such a means. Stone tools and cut marks on bones dating back more than 2 million years are evidence that animal carcasses were butchered. However, although these and later material remains indicate meat eating, they do not shed light on the energy contribution of animal compared with plant foods in the diet because plant foods do not leave such obvious traces. Se trec in revista o serie de populatii de vanatori-cilegatori sau semi-agricole, care desi consuma in cea mai mare parte produse vegetale au o stare de sanatate similara cu a celor cu diete bogate in carne, punand astfel la indoiala valabilitatea unui model unic al dietei, aratand ca mai degraba de a arata o adaptare genetica, diversitate dietelor arata ca omul poate supravietui si prospera cu o multitudine de diete. Unele populatii investigate de antropologi, desi aveau resurse de hrana animala, in lipsa sursei primare de carbohidrati, declarau ca nu au mancare! Quote However, because some hunter-gatherer societies obtained most of their dietary energy from wild animal fat and protein does not imply that this is the ideal diet for modern humans, nor does it imply that modern humans have genetic adaptations to such diets. It does, however, indicate that humans can thrive on extreme diets as long as these diets contribute the full range of essential nutrients. Hunter-gatherer societies in other environments were doubtless eating very different diets, depending on the season and types of resources available. Hayden stated that hunter-gatherers such as the !Kung might live in conditions close to the “ideal” hunting and gathering environment. What do the !Kung eat? Animal foods are estimated to contribute 33% and plant foods 67% of their daily energy intakes. Fifty percent (by wt) of their plant-based diet comes from the mongongo nut, which is available throughout the year in massive quantities. Similarly, the hunter-gatherer Hazda of Tanzania consume “the bulk of their diet” as wild plants, although they live in an area with an exceptional abundance of game animals and refer to themselves as hunters. Australian aborigines in some locales are known to have relied seasonally on seeds of native millet or a few wild fruit and seed species to satisfy daily energy demands. Some hunter-gatherer societies in Papua New Guinea relied heavily on starch from wild sago palms as an important source of energy, whereas most hunter-gatherer societies in California depended heavily on acorn foods from wild oaks. Although agriculture is relatively recent, most hunter-gatherer societies appear to have enthusiastically embraced it. For example, since well before the time of Columbus, tropical rain forests of South America have been inhabited not by hunter-gatherers but by hunter-gatherer-agriculturalists, small societies practicing shifting cultivation whose main crop was likely a single starchy carbohydrate. Contemporary ethnographers working in Amazonia noted that even when smoke racks are filled with game, if the carbohydrate staple becomes exhausted, the inhabitants say they have no food. In final se arata ca dietele acestor populatii erau bogate in fibre, cu o densitate calorica scazuta, de asemenea efortul fizic era mai mare decat in prezent, toate acestea contrastand cu dietele moderne caracterizate de o densitate calorica mare, continut mic de fibre, sedentarism, acestea fiind principalele cauze ale bolilor moderne si nu o neadaptare la dieta. Quote Medical examination has found little evidence of diseases of civilization in unacculturated Amazonian hunter-gatherer-agriculturalists, even though such people appear to have obtained a high percentage of their daily energy from a single plant cultivar for hundreds of years I suggest that it is the low energy density of most wild foods, both plant and animal, in combination with common features of human digestive physiology that have played the critical role in the lack of these diseases in such societies. Societies consuming a staple cultivar as well as wild foods likewise may have limited energy intakes because most cultivars lack many essential nutrients, necessitating the inclusion of other foods in the diet, and some are high in fiber (eg, cassava). In the natural environment, energy-dense, highly digestible foods of any type are generally rare. When available, such foods often serve not so much to satisfy that day's energy demands but rather to provide fat stores for use as energy during times of low food availability or, in women, to help meet the extra energy demands of reproduction. Because humans have large brains, it is particularly important that they are adept at storing excess dietary energy as fat because ketones can serve as an alternative fuel for the brain. Recent technology has circumvented this natural energy barrier by processing or otherwise altering both plant and animal foods such that much more energy can be ingested per day. In addition, most Westerners lead sedentary lifestyles, whereas the hunter-gatherer-agriculturalists I am familiar with work an average of ≥8 h/d, much of this work involving strenuous activities. Autorii studiului criticat au avut un raspuns la aceste critici Macronutrient estimations in hunter-gatherer diets Se mentioneaza ca studiul lui Lee pomenit nu a luat in calcul produsele obtinute prin pescuit si ca datele sale se refereau la cantitati si nu la procente din energia zilnica consumate sub forma de produse vegetale sau de origine animala. Apoi, nu produsele din vanat cresc cu latitudinea, ci doar cele obtinute din pescuit si scad cele vegetale. Quote Lee did not report the total food intakes derived from animal sources because he did not sum hunted and fished animal foods. This is one of the reasons our reanalysis of the Ethnographic Atlas is original and noteworthy. Milton's statement that “emphasis on hunting occurred only in the highest latitudes” is also inaccurate because our analysis of Lee's data showed that there is no correlation (Spearman's rho = 0.01) between dependence on hunting and latitude; on the contrary: as intakes of plant food decrease with increasing latitude, intakes of fished food increase and of hunted animal food stay constant—the same conclusion we reached with our original analysis. Autorii precizeaza ca nu au recomandat in studiul lor consumarea de carne grasa de la animalele crescute cu cereale, ci carne slaba in care profilul lipidic il imita pe acela al animalelor salbatice, adica preponderent mononesaturate si bogata in omega 3. Quote Within the nutritional community, it is common knowledge that the quantitative and qualitative lipid composition of domesticated meats is vastly different from that found in wild game. Game meat contains lower proportions of fat, especially saturated fat, than does meat from grain-fed domesticated animals, even on a whole-carcass basis. Nowhere in our article did we recommend that people should eat high-fat, domesticated livestock. Our take-home messages were that hunter-gatherer diets were higher in protein and lower in carbohydrate than are current Western diets or dietary guidelines and that this macronutrient balance may provide insight into potentially therapeutic diets. If any implication were to be inferred, it would be that dietary fat should emulate fat sources found in game meat and organs (high in n−3 fats, low in n−6 fats, and high in monounsaturated fats). Autorii contesta exemplele date cu populatiile citate care au o dieta preponderent in produse vegetale, considerandu-le nesemnificative. Quote The editorial deemphasizes the importance of animal foods in hunter-gatherer diets by citing 2 extreme and nonrepresentative societies, the Kung and the Hazda, both of which have been shown by the Ethnographic Atlas and modern quantitative studies to maintain high plant-animal subsistence ratios (67:33 and 56:44, respectively). Of the 229 hunter-gatherer societies listed in the Ethnographic Atlas, only 1 other society maintains a plant-animal subsistence ratio as high as that of the !Kung and only 13% maintain a ratio as high or higher than that of the Hazda. A compilation of the few available quantitative dietary studies in hunter-gatherers showed a plant-animal subsistence ratio of 41:59, which is similar to the aggregate value (45:55) we reported in our article. In sprijinul dietei propuse de ei, autorii aduc ca argumente beneficiile unei diete bogate in proteine. Quote Increases in low-fat dietary protein at the expense of carbohydrate may have therapeutic effects. Wolfe and Piche showed that the replacement of dietary carbohydrate with low-fat, high-protein animal foods improved blood lipids (LDL, VLDL, total cholesterol, triacylglycerol, and the ratio of total to HDL cholesterol). Furthermore, increased dietary protein may reduce the risk of coronary heart disease and reduce serum homocysteine concentrations while facilitating weight loss and improving insulin metabolism. In incheiere autorii pun din nou accent pe carnea slaba, si nu pe grasimea animalelor din comert. Quote Again, we do not recommend increases in intakes of domesticated animal fat, only of lean protein from lean animals, preferably protein that may also contain significant amounts of n−3 and monounsaturated fat such as that found in game meat. Consumption of low-fat dietary protein at the expense of carbohydrate is the nutritional pattern that is consistent with our species' evolutionary history and represents a viable dietary option for improving health and well-being in modern people. Further research is needed before this dietary pattern can be recommended without reservation, particularly in subjects with preexisting kidney disease. Dupa cum se observa unele critici nu sunt intemeiate si au fost clarificate de autorii studiului (cele referitoare la studiul mai vechi al lui Lee), insa unele critici raman in picioare. La cele referitoare la acuratetea datelor nu s-a raspuns, insa in studiul original chiar si autorii mentioneaza printre limitari acest lucru, plus o serie de estimari pe care ei insisi le-au introdus in ecuatie. Nu exista o dezbatere pe grasimile saturate. Autorii nu le recomanda, se insista pe carnea slaba, bogata in grasimi nesaturate, disputa pare sa fie pe chestiunea unei diete cu continut mare de carne, daca am avut vreodata preponderent pe parcursul evolutiei, o asemenea dieta sau lipsa datelor sau a acuratetei lor ne indruma catre o astfel de idee, si in fine daca suntem sau nu adaptati la o astfel de dieta. Dincolo de acuratetea datelor, raman o serie de intrebari lasate fara raspuns: - de ce este ignorata perioada dinainte de 2.5 milioane de ani? n-a contribuit si ea la modelarea genomului uman? - de ce numai populatiile cu dieta bogata in carne sunt considerate un model viabil, iar cele cu o dieta bogata in produse vegetale nu? ca doar ambele categorii au evoluat impreuna? - de ce modelul propus de autori nu se verifica in realitate? de exemplu populatiile care nu consuma multa carne ar trebui sa aiba o stare de sanatate mai precara (pentru ca nu sunt adaptati la o asemenea dieta) - de ce populatiile primitive semi-agricole sau agricole nu sufera de "bolile civilizatie"? ca doar nu sunt adaptati la acest tip de hrana neolitica - de ce intreaga umanitate pe parcursul a 10.000 de ani a prosperat, s-a dezvoltat la proportii nebanuite, desi modelul prezicea ca starea de sanatate trebuia sa se degradeze permanent si practic sa ne pasca extinctia, iar populatiile de vanatori-culegatori ar fi trebuit sa fie cele majoritare care sa supravietuiasca pana in zilele noastre - de ce aceste boli au aparut in a doua jumatate a sec xx si ce semnifica acest lucru? - de ce gasim in natura populatii cu diete atat de diverse si totusi lipsite de "bolile civilizatiei", nu este acest lucru o dovada ca teoria neadaptarii noastre genetice la un anumit tip de hrana nu este valabila, si ca alti factori determina aceste boli? Dupa cum vad eu lucrurile in acest moment, daca dieta paleo ramane la stadiul "sa consumam grasimi saturate ca asa am evoluat", impreuna cu diabolizarea carbohidratilor, nu are sanse mari sa treaca de stadiul de "fad diet", in cativa ani febra asta paleo se va stinge. Daca se revine la radacini, si anume la dieta asa cum este ea descrisa in literatura stiintifica, are o sansa sa supravietuiasca, depinde insa de modelul propus. Daca modelul va fi prin excluziune, adica acesta este singura dieta la care suntem adaptati, atunci nu va rezista criticii din interiorul comunitatii stiintifice, pur si simplu sunt mult prea multe argumente impotriva unui astfel de model. Daca insa va functiona prin incluziune, adica acest tip de dieta este unul din multele modele viabile, dar nu singurul, atunci probabil va putea rezista. |
#43
Posted 27 January 2015 - 21:50
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O sa prezint ultimul studiu, din 2010, despre dieta paleo Paleolithic-Nutrition-Twenty-Five Years-Later Studiul le apartine lui Melvin Konner si Boyd Eaton, autorii primului studiu din 1985. Acest studiu, realizat la 25 de ani de la publicarea studiului original, vine sa aduca la zi cercetarile in domeniu.
Se trec in revista criticele aduse primei lucrari stiintifice. Quote Our papers and book were greeted with a certain amount of media attention, including ridicule, some of it based on the short life span of hunter-gatherers. This point had of course not been lost on us; as we had shown in extensive reviews of the primary literature, 30 to 35 years was roughly the average life expectancy at birth of preindustrial populations generally, due mainly not to the absence of older people but to extremely high infant and child mortality. Death in HGs was overwhelmingly due to infectious diseases we now control, and older HGs rarely got or died of coronary artery disease, diabetes mellitus, or chronic obstructive pulmonary disease, among other ailments common in societies like ours. We had not proposed that they were healthier in absolute terms, just that absent infection and osteoarthritis, they rarely had the chronic diseases we commonly have. Our review of various health measures in HG and other nonindustrial populations showed that average HG serum total cholesterol was always below 135 mg/dL, aerobic fitness of average men was in the athletic range for Western populations, and diabetes mellitus prevalence was very low. In the mid-1980s, the standard recommendations, based on clinical and experimental research, were urging Americans in most cases to change their diet in a direction consistent with the HG model. However, there were important differences. Intakes of saturated fat, salt, and refined carbohydrate levels were markedly lower in HGs than in the standard recommendations, whereas protein and fiber content were far higher. Cholesterol intake was also higher; both cholesterol and carbohydrate intake were roughly the same in HGs as in the average American diet, although the spectrum of carbohydrates was very different. We did not then and do not now propose that Americans adopt a particular diet and lifestyle on the basis of anthropological evidence alone; formal recommendations must rest on carefully executed laboratory, clinical, and epidemiological studies. Rather, we suggested that the standard recommendations of the time needed more research in light of the HG model. Dupa cum se observa speranta scazuta de viata era datorata mortalitatii infantile si bolilor infectioase. De remarcat nivelul extrem de scazut al colesterolului in populatiile de vanatori-culegatori de sub 135 mg/dL, puneti in oglinda cu dogmele din blogosfera low-carb/paleo care afirma ca nu este important colesterolul total. De retinut si faptul ca recomandarile in domeniu tind sa se alinieze cu cele reiesite din studiul acestor diete cu cateva diferente legate de tipul carbohidratilor, colesterol. Interesant ca ponderea grasimilor saturate in dietele paleo este mai mica decat recomandarile in domeniu. Autorii precizeaza minusurile studiului original si fac un sumar el evolutiei dietei pe parcursul a catorva milioane de ani si adaptarile biologice rezultate. Quote Some analyses in the past decade have suggested that we underestimated the proportion of meat in HG diets. This is of substantial potential importance in estimating the intake of total fat, protein, carbohydrate, and fiber in those diets. However, this position has not gone unchallenged. It is clear that ancestral human diets derive from higher primate diets that were overwhelmingly plant based, supplemented by insects and (in some species) a small amount of animal flesh. Fossil evidence shows that this pattern continued to be true of early bipedal hominids (between 6 and 2 million years ago [mya]), with a likely particular emphasis on underground storage organs (USOs; tubers) and on large protected nuts and seeds. Reliance on animal flesh increased substantially after 2 mya with the evolution of Homo habilis and especially Homo erectus, a species clearly capable of hunting large game, an ability shared by modern humans. However, much evidence points to continued significant (if not predominant) dependence on plant foods. Consider the human gut. It is substantially smaller than the value predicted from the primate regression of gut on body weight (indeed, it is almost gram for gram reduced in proportion to excess human brain weight). This is due in part to concentration of calories, both in plant foods (fruit and nuts as opposed to leaves and grass) and, later, meat, but it is clear that cooking played a key role beginning at least 0.23 mya and perhaps much earlier, reducing the need for human digestion of both plant foods and animal flesh. However, the human gut retains many structural and metabolic features of the herbivore/frugivore higher primate gut, departing in important ways from the typical gut of top carnivores. Din nou se pune accent pe faptul ca produsele vegetale au jucat un rol important in evolutia noastra o buna bucata de timp, apoi carnea si gatitul alimentelor. Nimic din sfaturile diversilor "guru" care recomanda limitarea fructelor pentru ca ingrasa. Sistemul nostru digestiv si metabolismul seamana in multe privinte cu acelea ale primatelor superioare, cu diferente majore fata de carnivore. Se aduc precizari cu privire la importanta flexibilitatii in adaptarea la diverse diete si importanta produselor de origine marina. Quote Furthermore, the archeological/paleontological record makes it clear that ancestral populations relevant to the origin of our species (anatomically modern Homo sapiens) relied on a variety of food sources in significantly varying environments; indeed, flexibility in adaptation may have been central to human evolution and we now speak of EEAs (environment of evolutionary adaptedness) rather than a single EEA. This range undoubtedly included substantial reliance on plant foods in many times and places. To support a very long human childhood, a unique human pattern of postweaning provisioning evolved, including contributions of animal flesh from fathers and of plant foods from mothers and grandmothers. Fathers also contributed meat to their pregnant and nursing wives. Children themselves foraged in many HG groups, collecting substantial amounts of plant foods, shellfish, and some small game such as lizards and birds, although mastery of hunting was delayed well into adulthood Finally, it has become clear since our initial publications that marine, lacustrine, and riverine species were important sources of animal flesh during the evolution of modern Homo sapiens and may have played a role in the evolution of brain ontogeny. In any case, shellfish and other aquatic animal species must be considered part of the spectrum of ancestral nutrition adaptations. Thus, there have been changes in the way we estimate the likely diets of ancestral HG populations, admitting more variability. However, the best current estimates restrict most of that variability to a range from 35% to 65% animal flesh, including substantial marine animal resources for at least 0.2 million years. As we will see, these new estimates do not affect the direction of the great majority of our recommendations. Se observa un rol al sexelor in contributia produselor vegetale si de origine animala in dieta copiilor si rolul produselor de origine marina in dezvoltarea creierului. Lipidele in dietele paleo Quote It was widely accepted by the late 1980s that saturated fat (SF) intake in the typical modern diet is far too high and that the C-14 and C-16 fatty acids are a major contributor to endemic atherosclerosis underlying most coronary artery disease and stroke, the first and third leading causes of death. Through energy load, total fat (TF) intake is an important contributor to endemic obesity and the growing epidemic of T2DM. Standard recommendations suggested that TF be reduced to no more than 30% of calories and that the ratio of SF to unsaturated fat be reduced markedly. At the time, we estimated that in the HG diet, TF contributed about 20% of calories, including about 6% SF, a level of restriction deemed by most authorities to be too difficult to achieve. On the basis of new analyses of HG diets, we have raised the estimated range of their likely TF intake to 20%-35%. Both low-fat (20%) and high-fat (40%) diets have been shown to aid in weight loss given appropriate caloric restriction and adherence, but it has also been shown that very low TF may not only prevent or retard atherosclerosis but, combined with other lifestyle changes, partly reverse established athero-sclerotic plaques. However, TF is only part of the story. Game animals have more mono and polyunsaturated fatty acids (MUFA and PUFA) than supermarket meat. It used to be recommended that SF intake be less than 10% of total energy, but according to the Institute of Medicine (IOM), any increase raises cardiac risk. 40 (However, recent evidence suggests that the C-14 and C-16 saturated fatty acids, and not C-18 stearic acid, are the chief serum cholesterol-raising components of animal fat.) Especially given their high estimated intake of marine animal flesh, PUFA intake would have been nearly twice the present level of 15 g/d, due almost entirely to a greater proportion of cardioprotective ω-3 forms. The resulting ω-6:ω-3 ratio of about 2:1 contrasts with the current ratio of about 10:1, with 8:1 recommended. Nu exista nici o contradictie intre autori si consensul stiintific referitor la grasimile saturate, in schimb majoritatea autorilor de carti low carb/paleo sunt in vadita contradictie. Ponderea medie a lipidelor din dietele paleo se afla in limitele recomandarilor oficiale. Se recunoaste rolul si importanta unei diete low fat in combinatie cu alti factori de a reduce arterioscleroza. Carnea animalelor salbatice este saraca in grasimi si structura acestora inclina balanta inspre cele nesaturate, contrar opiniilor din comunitatea low carb/paleo care recomanda carnea grasa si grasimile saturate in general. Lipidele omega 3 erau mai crescute in dietele paleo. Colesterolul Quote We reported that HG cholesterol intake was similar to or higher than that of modern Americans. Since muscle cell membranes have as much cholesterol as fat cell membranes, low-fat game meat and fish still had high cholesterol content. HG diets suggested that discordance did not apply to dietary cholesterol levels and that concern about them would lead to unnecessary restriction of low-fat meat and fish. It has since become clear that dietary cholesterol is not a major independent driver of serum cholesterol or its fractionation. The major dietary determinants are the cholesterol-raising fatty acids, with an additional contribution from dietary refined carbohydrates, suggesting that for most people, restriction of these 2 components of diet is sufficient to keep serum cholesterol and the low-density lipoprotein (LDL)/high-density lipoprotein (HDL) ratio very low HG cholesterol intake is estimated at 480 mg/d, nearly 200 mg/d higher than recommendations. This level would be expected to elevate serum cholesterol about 0.2 mmol/L (8 mg/dL), but the impact is far outweighed by their lower intake of cholesterol-raising fatty acids. In addition, high-protein intake can be expected to have further mitigated the atherogenic effects of fat. Colesterolul din dietele paleo era mai ridicat decat recomandarile oficiale, insa apropiat de consumul uzual din dietele de azi (recomandarile oficiale nu prea sunt repectate). Insa exista 2 factori care contribuie la diminuarea efectelor acestui aport crescut: contributia mica a grasimilor saturate si consumul ridicat de proteine cu efect de scadere a colesterolului. Nu uitati colesterolul total in randul acestor populatii este in general sub 140. Proteinele Quote In the 1980s, most dietary advice called for a reduction in protein intake, especially in the form of meat. This was not consistent with the HG model, and we reasoned that the ill effects of meat were mainly due to its almost inevitable association in our culture with high cholesterol-raising fat intake. Another concern raised by some authorities was that nitrogen load might become excessive with high meat consumption. Subsequent analyses have substantially increased the estimate of HG protein intake, but there is no evidence as yet that lean meat (similar to wild game) intake corresponding to the levels in the average HG diet has adverse health consequences. It has, in fact, been shown that although diets rich in lean beef raise arachidonic acid concentrations (a negative), their long-chain ω-3 PUFA content, plus the intrinsic hypocholesterolemic effect of protein, results in a serum lipid profile thought to be protective against atherosclerosis. To the extent that HG diets included aquatic species, this effect would have been further enhanced. Explicatia data de autori in privinta recomandarilor oficiale mai vechi de a limita carnea este pusa pe seama faptului ca aceasta carne era insotita mai mereu de grasime saturata, cu efect de ridicare a colesterolului, insa efectul carnei slabe este invers. Un rol il joaca si prezenta lipidellor de tip omega 3. Carbohidratii si fibrele Quote Americans obtain about half their daily energy from carbohydrate (CHO), including 15% from added sugars. HG CHO consumption ranged widely, from about 35%-65%, with perhaps 2%-3% from honey. Cereal grains (85% refined) are our largest single CHO source, with dairy products another significant contributor. HGs had little of either, so nearly all CHO came from fruits and vegetables. The IOM recommends a CHO range from 45%-65% of total energy, with no more than 25% from added sugars. This recommendation would approximate HG total CHO intake, but qualitative equivalence would require that nearly all CHO come from fruits and vegetables, with a minimum from cereal grains, none refined. Uncultivated vegetables and fruits are markedly more fibrous (13.3 g fiber/100 g) than commercial ones (4.2 g/100 g) Our 1985 estimate was limited to crude fiber, but soon thereafter data on total fiber content became available and suggested that total fiber intake (TFI) would have averaged 150 g/d. With lower estimates of total HG CHO intake, the estimate could be as low as 70 g/d but not lower. The IOM suggested 25 g/d for women and 38 g/d for men, a bit more than twice the current median intake, but found insufficient evidence to set a tolerable maximum. High fiber intake may adversely affect mineral bioavailability, especially in the presence of phytic acid, a prominent constituent of many cereal grains but minimal in uncultivated fruits and vegetables. Fruit and vegetable fiber is also more completely fermented than cereal fiber, enhancing its advantages. Finally, the HG ratio of insoluble to soluble fiber was much higher than at present, approximately 1:1. Carbohidratii in dietele paleo variau destul de mult, insa se incadreaza in limitele recomandarilor oficiale. Asta din nou in opozitie cu recomandarile care vin dinspre low carb de a se limita ponderea acestora in dieta. Fibrele se pare ca au contribuit chiar mai mult, in dietele paleo, decat estimarile mai vechi, intre 70-150 g/zi, din nou in opozitie cu parerile majoritare acelora din low carb care cred ca acestea nu sunt importante sau dimpotriva sunt chiar daunatoare (sunt chiar opinii conform carora aceste fibre ar leza intestinul gros in tranzitul lor). Sodiul si potasiul si balanta acido-bazica Quote Both sodium (Na + ) intake (768 mg/d) and the sodium/ potassium (Na + /K + ) ratio were found to be extremely low in HG diets. A meta-analysis of prospective observational studies conducted from 1966 to 2008 (19 independent samples from 13 studies including 177,000 participants) concluded that reducing salt intake from the estimated adult average of 10 g/d to the World Health Organization (WHO) recommendation of 5 g/d would be associated with a 23% difference in the rate of stroke and a 17% difference in the overall rate of cardiovascular disease (CVD), preventing more than 4 million deaths worldwide annually. Two randomized controlled trials in which dietary interventions reduced Na + intake by 25%-35% achieved small but significant reductions in BP over a 1.5 to 4 year period, but follow-up 10-15 years later showed a reduced risk of cardiovascular (CV) events of 25%. Most recently, a well-validated computer simulation projected the effect on U.S. mortality from CHD and stroke of linearly reducing salt intake by 0-3 g/d from current estimates of 10.4 and 7.3 g/d for adult males and females, respectively; the estimated reduction of the number of deaths per year was 44,000 to 92,000. Due in part to the changes in the K+ /Na+ ratio, acid base balances have also changed markedly. In addition to the roughly 10-fold difference between estimated HG Na+ intake and ours, their K+/Na+ ratio was probably at least 5:1; now Na+ exceeds K+ , due to added Na+ and low consumption of K+ rich fruits and vegetables. The latter would also have driven systemic pH toward alkalinity, whereas cereal grains and most dairy products are net acid yielding. Over decades, the corrective metabolic measures needed to offset acid-yielding diets cause urinary calcium loss, accelerated skeletal calcium depletion, calcific urolithiasis, age-related muscle wasting, and deteriorating renal function. A recent effort to model the net endogenous acid-producing potential of the diets of 229 HG groups suggests that the majority had a net positive acid load, but many of these had adaptations that could not have been ancestral ones (eg, equestrian hunting and circumpolar residence). Those HG diets that were predominantly plant based (such as those of ancestral East African populations) would have had a more favorable net negative acid load, so that an earlier estimate, which suggested an overall alkaline net load for HG diets, remains pertinent to the model. Sodiul era scazut si balanta Na/K era negativa, raportul K/Na era 5:1, in dietele paleo, acum este invers, mult sodiu si mai mult sodiu decat potasiu. Dietele paleo asa cum erau ele in randul populatiilor care au trait in Africa inainte de valurile migrationiste erau bogate in produse vegetale si mai degraba alcaline. Despre dietele la moda! Quote Recent dietary fads, based on unproven theories of metabolism, claim that very low carbohydrate intake combined with high protein and fat consumption can safely produce weight loss. That this kind of diet can produce at least temporary weight loss has been demonstrated, and several studies now show that levels of lean meat and fish intake higher than those in many officially recommended diets are as safe or safer for some groups of patients. We continue to believe that the risk associated with the consumption of meat is almost entirely explained by the high proportions of TF and especially SF in commercial meats. Neither the protein content of meat nor the cholesterol content of cell membranes has been shown to adversely affect health at the (fairly high) level characteristic of HG diets. Reduction of carbohydrates to extremely low levels is not consistent with the HG model, but neither is a very high CHO, meat as a condiment type diet; furthermore, CHO sources are important. HG CHO came from fruit, vegetables, and nuts, not from grains. Refined, concentrated CHOs such as sucrose played virtually no role, and the consumption of plant CHO necessarily resulted in high fiber intake. If we were to rebuild the food pyramid along HG lines, the base would not be grains but fruits and vegetables, which could be chosen to provide adequate fiber content. The second tier would be meat, fish, and low-fat dairy products, all very lean. Whole grains might come next (although even these were very unusual for HGs), whereas fats, oils, and refined carbohydrates would occupy the same very small place at the top, essentially functioning as condiments in a healthy diet. Aceasta este probabil cea mai directa si evidenta dovada ca paleo nu este low carb si high fat. De remercat ca autorii plaseaza grasimile pe ultimul loc, ca si condiment, pana si cerealele nerafinate (in cantitati mai mici, evident) sunt plasate inainte, intr-o piramida nutritionala de tip paleo. In incheiere autorii mentioneaza importanta eexercitiilor fizice, chiar si de mica intensitate, precum mersul si importanta validarii acestei diete prin studii ulterioare. Quote As for other aspects of lifestyle, tobacco products, rare in HG environments, have been the targets of increasingly strong societal restriction, and we know that the frequency and duration of exercise, including walking and other less intense exercise, should be much higher than it is and should include resistance and flexibility as well as cardiovascular components. Interestingly, we had been skeptical of the notion, common in the 1980s, that walking was not an adequate exercise because half of our HG ancestors the women exercised in this manner and did very little running. The subsequent finding that walking and other moderate exercise also reduce the risk of cardiopulmonary disease was consistent with the HG model. Not every prediction of the HG model will result in the best recommendation. The case of ethanol consumption, extremely low before the invention of agriculture, departs from the model. A number of studies show that mild to moderate ethanol intake reduces cardiovascular risk, at least against the background of a modern diet. The ease with which ethanol intake progresses to levels that pose a wide range of other health risks suggests that we were not set up by our evolution to handle this compound without difficulty, but the positive value of small amounts shows that the HG model cannot answer all questions Although an anthropological model cannot be accepted at face value only the best clinical, experimental, and epidemiological research can finally justify recommendations we can be increasingly guided in this research by such a model. Meanwhile, we can keep an open mind about what we may learn from our remote ancestors. Dupa cum se observa autorii nu sunt dogmatici in privinta alcoolului, care in cantitati mici este benefic, chiar daca nu este paleo. Se pune accentul pe faptul ca aceasta ipoteza a dietelor paleo prin ea insasi nu are greutate, decat prin prisma validarii ei prin studii clinice si epidemiologice. Cat de mult difera acesta atitudine echilibrata si in spiritul cercetarii stiintifice de avantul propagandistic al unora, care vand tot soiul de teorii hazardate, ca pe adevarul absolut! 
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Cereale si lacatate in dieta paleo.jpg 51.86K
16 downloadsAceste planse sunt dintr-o prezentare a lui Boyd Eaton (unul din autorii studiului de fata, a celui din 1985 si a celui din 2000) din 2012 asupra dietei paleo. Long-Term Paleo: What Happens if You Follow the Ancestral Health Protocol for Thirty Years? A starnit atunci valuri de soc in comunitatea low carb/paleo cand a precizat ca in cazul persoanelor sanatoase consumul moderat de cereale si produse lactate este permis. In privinta lactatelor n-a fost asa o mare problema, ca oricum comunitatea este rupta in doua in ceea ce priveste acest subiect, dar sa spui ca e ok sa consumi cereale!!! O comunitate care a fost crescuta in ideea ca ceralele sunt hrana lui Satan, nectarul Bestiei, a digerat cu greu aceasta erezie!!! Insa lucrurile au evoluat, intre timp chiar din sanul comunitatii au aparut voci care sustin ca glucidele (orezul, cartofii) nu sunt chiar atat de rele si chiar in favoarea cerealelor integrale s-au auzit voci. |
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Posted 30 January 2015 - 22:23
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In 2011 US News and World Reports a publicat un top al dietelor, in care dieta paleo a iesit pe ultimul loc. Acest lucru a determinat un raspuns ferm al lui Loren Cordain care a contestat faptul ca nu prea exista studii asupra dietei paleo, pe baza carora sa se poata trage concluzii, asa se plangeau expertii care au alcatuit acest top. Am sa prezint toate studiile asupra dietei paleo, asa cum au fost ele mentionate de Cordain. Acestea sunt:
1. Marked Improvement in Carbohydrate and Lipid Metabolism in Diabetic Australian Aborigines After Temporary Reversion to Traditional Lifestyle 1984 Studiul a cuprins 10 aborigeni (5 femei si 5 barbati), diabetici , cu varsta in jur de 50 de ani, care au tinut o dieta traditionala. S-au observat efecte benefice in privinta trigliceridelor, glicemiei si insulinei. Colesterolul total a scazut putin, au scazut puternic VLDL si HDL, iar LDL a crescut putin. Pacientii au slabit, au procesat mai bine glucoza si sensibilitatea la insulina a crescut. In primele 2 saptamani dieta a constat in 75% carne de vaca, restul de 25% fiind compus din carne de cangur, testoase, peste, tuberculi si miere. In procente: 50% P, 10% C, 40% L. In urmatoarele 2 saptamani diata a constat din 80% peste si 20% carne de pasare, cangur si carne de crocodil. In procente: 80% P, <5% C, 20% L. In ultimele 4 saptamani dieta a constat din 36% carne de cangur, 19% peste, 28% tuberculi si 17% carne de crocodil, pasari, testoase, smochine si miere. In procente: 54% P, 33% C, 13% L. Pe parcursul celor 7 saptamani dieta a avut intre 1100 si 1300 Cal. Dieta a fost, dupa cum se observa, foarte bogata in proteine, slaba in grasimi (cu exceptia primelor 2 saptamanai) si hipocalorica. 2. A Palaeolithic diet improves glucose tolerance more than a Mediterranean-like diet in individuals with ischaemic heart disease 2007 29 de persoane, suferind de boala cardiaca plus intoleranta la glucoza sau diabet de tip 2, au consumat o dieta paleo timp de 12 saptamani. Pacientii au slabit si toleranta la glucoza s-a imbunatatit independent de slabire (scaderea in talie). In procente 27.9% P, 40.2% C, 26.9% L, 7.7% SFA. Caloriile au fost in jur de 1350. Dieta este bogata in proteine si nu in grasimi, hipocalorica. 3. Effects of a short-term intervention with a paleolithic diet in healthy volunteers 2007 Studiul a cuprins 14 subiecti, durata a fost 3 saptamani. Pacientii au slabit, au scazut in talie, a scazut presiunea sanguina.In procente 23.9% P, 40% C, 35.8% L, SFA 5.5%. Caloriile au fost in jur de 1600. Dieta este bogata in proteine, medie in lipide (dupa modelul "clasic" 60-70% grasimi) si hipolcalorica. 4. Metabolic and physiologic improvements from consuming a paleolithic, hunter-gatherer type diet 2008 Studiul a cuprins 9 persoane sanatoase si a durat 10 zile. Subiectii si-au imbunatatit toleranta la glucoza, sensibilitatea la insulina, profilul lipidic (au scazut colesterolul total, LDL, trigliceridele). In procente 30% P, 38% C, 32% L, SFA 4.5%. Dieta a fost una eucalorica (de mentenanta) 2700 Cal. Studiul nu a avut grup de control. Dieta este echilibrata intre macronutrienti, insa este bogata in proteine dupa criteriile din recomandarile oficiale. 5. Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes: a randomized cross-over pilot study 2009 Studiul a cuprins 13 pacienti diabetici si durata a fost de 3 luni. Subiectii au slabit, au scazut in talie, si-au imbunatatit toleranta la glucoza, a crescut sensibilitatea la insulina, au scazut trigliceridele. In procente 24% P, 32% C, 39% L, SFA 10.8%. Dieta a avut in jur de 1600 Cal. Dieta a fost bogata in grasimi doar dupa criteriile oficiale, nu si dupa cifrele vehiculate de cei din low carb/paleo, glucide aproape o treime si proteinele in limitele obisnuite pentru low carb, insa multe dupa criteriile oficiale. Dieta a fost hipocalorica. 6. A paleolithic diet is more satiating per calorie than a mediterranean-like diet in individuals with ischemic heart disease 2010 29 de persoane, suferind de boala cardiaca plus intoleranta la glucoza sau diabet de tip 2, au consumat o dieta paleo timp de 12 saptamani. Este acelasi studiu de la punctul 2, insa aici s-a reliefat alt aspect: satietatea. Aceasta a fost similara cu cea din dieata mediteraneeana, insa cum dieta paleo a avut calorii mai putine (in conditiile uni consum ad libitum), satietatea per calorie a fost mai mare in cazul dietei paleo (cel mai probabil datorita aportului crescut de proteine, cu efect cunoscut de crestere a satietatii). In procente 27.9% P, 40.2% C, 26.9% L, 7.7% SFA. Caloriile au fost in jur de 1350. 7. A Palaeolithic-type diet causes strong tissue-specific effects on ectopic fat deposition in obese postmenopausal women 2013 10 femei au consumat o dieta paleo timp de 5 saptamani. Dieta a fost saraca in carbohidrati (dupa standardele oficiale recomandate), saraca in grasimi saturate, bogata in proteine, bogata in grasimi MUFA. Pacientele au slabit, si-au redus caloriile cu 25% au scazut colesterolul total, LDL, trigliceridele, raportul LDL/HDL. In procente 30% P, 30% C, 40% L, SFA 13%. Dieta a avut in jur de 1900 Cal. Este o dieta bogata in grasimi si proteine, insa se observa un echilibru relativ intre macronutrienti. Dieta a fost hipocalorica relariv la dieta anterioara. 8. Subjective satiety and other experiences of a Paleolithic diet compared to a diabetes diet in patients with type 2 diabetes 2013 Studiul a cuprins 13 pacienti diabetici si durata a fost de 3 luni. Este acelasi studiu de la punctul 5, insa acum s-a urmarit un alt efect: satietatea, care pe o dieta paleo a fost mai mare per calorie, insa ambele diete au produs un nivel similar de satietate luate in ansamblu. In procente 24% P, 32% C, 39% L, SFA 10.8%. Dieta a avut in jur de 1600 Cal. 9. Long-term effects of a Palaeolithic-type diet in obese postmenopausal women: a two-year randomized trial 2014 Practic acesta este singurul studiu pe termen lung, care studiaza efectele unei diete paleo. Studiul a avut ca subiecti 70 de femei obeze, cu varsta medie de 60 de ani si care au consumat o dieta paleo ad libitum, timp de 2 ani. Grupul de control a consumat o dieta nordica conform recomandarilor oficiale. Ambele grupuri au slabit, ambele grupuri si-au imbunatatit factorii de risc, insa la 6 luni grupul care a urmat dieta paleo a avut rezultate mai bune, care insa n-au putut fi mentinute la 24 de luni comparativ cu dieta nordica. In procente: 30% P, 30% C, 40% L, SFA 10.5%, MUFA+PUFA 28-29%. Dieta a avut in medie 1600 Cal. Dieta a fost bogata in grasimi nesaturate si in proteine. Dupa standardele oficiale a fost scazuta in carbohidrati insa dupa normele low carb/paleo, destul de incarcata de carbohidrati. Concluziile autorilor: Quote Results Both groups significantly decreased total fat mass at 6 months (−6.5 and −2.6 kg) and 24 months (−4.6 and −2.9 kg), with a more pronounced fat loss in the PD group at 6 months (P<0.001), but not at 24 months (P=0.095). Waist circumference and sagittal diameter also decreased in both groups, with a more pronounced decrease in the PD group at 6 months (−11.1 vs. −5.8 cm, P=0.001 and −3.7 vs. −2.0 cm, P<0.001, respectively). Triglyceride levels decreased significantly more at 6 and 24 months in the PD group versus the NNR group (P<0.001 and P=0.004). Nitrogen excretion did not differ between groups. Conclusions A PD has greater beneficial effects versus an NNR diet regarding fat mass, abdominal obesity and triglyceride levels in obese postmenopausal women; effects not fully sustained for anthropometric measurements at 24 months. Adherence to protein intake was poor in the PD group. The long-term consequences of these changes remain to be studied. Cam acestea sunt studiile pe care se bazeaza dieta paleo. Daca excludem studiile care se repeta, raman 7 studii din care unul singur pe termen lung, iar acesta din urma are concluzii din care reiese ca aderenta la o dieta bogata in proteine este scazuta si rezultatele nu se mentin decat partial pe termen lung. Nu este de mirare ca dieta a fost plasata pe ultimul loc in ultimii ani de catre Us News and World Report, nu ca acestia ar avea ultimul cuvant de spus asupra acestei diete, insa au scos in evidenta un lucru: lipsa datelor elocvente, adica studii cu un numar mare de participanti si desfasurat pe o perioada lunga de timp. De remarcat ca, in afara unei singure diete, toate celelalte au fost hipocalorice. Se pune intrebarea daca rezultatele bune au fost datorate dietei paleo sau dietei hipocalorice. Este stiut faptul ca in literatura stiintifica mai toate studiile care opereaza cu diete hipocalorice, obtin imbunatatiri ai factorilor de risc si pierderea in greutate indiferent de structura macronutrientilor. Am facut un tabel din care sa reiasa mai bine structura acestor diete in privinta macronutrientilor. Studiul cu nr. 6 nu l-am pus pentru ca este acelasi cu studiul nr. 2, studiul 8 este acealsi cu studiul 2. Fata de referintele lui Loren Cordain am adaugat studiile lui Ryberg si Mellberg care au fost efectuate ulterior. Ca si concluzie, aceste diete nu sunt nici pe departe miticele diete cu 60-70% grasimi, majoritatea saturate, vehiculate in cercurile low carb/paleo. Sunt diete high protein si cu lipidele si glucidele in proportii asemanatoare. Nu sunt diete bogate in grasimi saturate.
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28 downloadsUitati-va la ponderea grasimilor saturate!!! |
#45
Posted 09 February 2015 - 18:52
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Daca pana acum am prezentat dieta paleo asa cum reiese ea din lucrarile stiintifice, m-am gandit sa fac o prezentare a istoriei dietelor paleo prin prisma cartilor aparute pe aceasta tema. Printre acestea se afla si unele scrise de antropologi cu expertiza, insa cele mai multe nu (mai ales acestea din urma au modelat cu precadere conceptia despre dieta paleo). Am sa prezint si problemele, contradictiile care au aparut intre diverse grupari din comunitatea paleo.
In 1939 apare cartea Nutrition and Physical Degeneration scrisa de Weston Price. De profesie stomatolog a investigat relatia dintre dieta si sanatatea dintilior. Mai tarziu preocuparile sale s-au axat pe zona de nutritie. Este unul dintre autorii care s-au interesat de dietele populatiilor primitive. Site-ul fundatiei cu acelasi nume este foarte influent in comunitatea low carb/paleo. Price nu considera carbohidratii daunatori si nici cerealele. In 1946 apare Not by bread alone scrisa de Vilhjalmur Stefansson un explorator care s-a interesat de dieta inuitilor. Este des citat in cercurile paleo, ca un argument in favoarea dietelor keto. 1n 1952 este scrisa Primitive man and his food de catre Arnold Paul De Vries. In mare este o imitatie a lucrarii lui Price, in care investigheaza dietele populatiilor primitive si starea lor de sanatate. In 1960 vede lumina tiparului Strong Medicine. Autorul ei este Blake F. Donaldson, un medic cardiolog care cautand o dieta eficienta pentru pierderea in greutate pentru pacientii sai, a descoperit ca o dieta bazata pe carne este eficienta. A colaborat cu Stefansson in elaborarea dietei. Una din frazele emblematice ale cartii este "There are probably only two perfect foods - fresh fat meat and clean water". Intr-o prima etapa a dietei se permite doar carnea in alimentatie, apoi se permite si consumul de cartofii sau mazare, nu insa si cerealele sau zaharul. Considera ca pana si zaharul dintr-o guma de mestecat poate opri procesul de slabire. N-are o parere buna nici despre oua, lapte, branza si majoritatea vegetalelor. Mesajul cartii ne duce la concluzia ca oamenii sunt mai degraba carnivori decat omnivori. In 1975 apare The stone age diet: based on in-depth studies of human ecology and the diet of man scrisa de gastroenterologul Walter L. Voegtlin.Aceasta poate fi considerata prima carte care are ca subiect principal dieta paleo, a fost tiparita in editie limitata chiar de catre autor. Este depasita in ceea ce priveste calitatea informatiilor, de pilda cuprinde idei bizare precum aceea de a consuma fructele si legumele mai ales sub forma gatita, este permis consumul de paine, macaroane, carofi, orez, zilnic, dar in cantitati mici. Acesta carte este considerata inceputul miscarii paleo de catre multi, insa la vemea ei a trecut aproape neobservata. In 1987 apare o alta carte despre dieta paleo The Stone Age Diet scrisa de un practicant al medicinei alternative Leon Chaitow. Nu este des mentionata in cercurile paleo. In 1989 apare prima carte despre dieta paleo scrisa de catre oameni de stiinta The Paleolithic Prescription: A Program of Diet & Exercise and a Design for Living Autorii nimeni altii decat parintii miscarii paleo Eaton si Konner, cei cu studiul din 1985. La aceasta carte a contribuit si Marjorie Shostak. Tot in acelasi an aceasta tripleta a mai scos pe piata o carte despre dieta paleo Stone Age Health Programme: Diet and Exercise as Nature Intended. Aceste carti n-au avut impactul pe care-l au acum cartile despre paleo, probabil din cauza lipsei unui mediu de propagare a informatiei (internetul), lipsei unui context propice (nu exista, ca acum, nebunia cu dietele low carb) si probabil din cauza tonului retinut al autorilor, asa cum reiese si din studiile anterioare. Tot in 1995 apare o carte care va capata ulterior o statura aproape mitica NeanderThin scrisa de Ray Audette. Autorul suferea de mai multi ani de artrita reumatoida, apoi find diagnosticat cu diabet si-a vazut distrusa sansa la o viata normala. A cautat o modalitate de tratament si dupa o lunga perioada de studiu a dat peste lucrarea din 1985 al lui Eaton si Konner. A inceput sa tina o dieta de tip paleo si starea sa de sanatate s-a imbunatatit semnificativ. S-a hotarat sa scrie o carte, insa neavand pregatire medicala, a decis sa apeleze la autori cu expertiza in domeniu. Printre cei consultati au fost: Michael Eades (ce avea sa scrie un an mai tarziu Protein Power), Loren Cordain, Boyd Eaton. A fost si ramane una din cele mai documentate carti scrise despre dieta paleo de un nespecialist. In 2001 apare cartea cea mai influenta scrisa de un specialist, Loren Cordain The Paleo Diet Este cel care a inventat titulatura paleo diet ( pana la el se folosea expresia paleolithic diet) ; se considera intemeietorul miscarii paleo.Totusi miscarea paleo n-a luat avant decat 9-10 ani mai tarziu, cand Gary Taubes a inceput sa-si piarda suflul, opera sa fiind sever criticata chiar din interiorul comunitatii, fiind descoperite erori grave in documentare, interpretare si lacune atat de severe incat au afectat aproape iremediabil increderea in opera sa. S-a produs o miscare haotica in acei ani care a coincis cu ascensiunea miscarii paleo; comunitatea low carb si-a gasit astfel o noua casa, insa linistea nu avea sa dureze mult. Acei ani 2002-2010 au fost totusi anii lui Taubes si ai miscarii low carb. In 2009 apare cartea Primal Blueprint a lui Mark Sisson, probabil cea mai influenta carte scrisa de un nespecialist. A dezvoltat o adevarata industrie in jurul ei (suplimente, conferinte platite, alte carti etc.) in 2010 apare Food and Western Disease: Health and nutrition from an evolutionary perspective scrisa de un alt cercetator al dietelor paleo Staffan Lindeberg. Cartea n-a gasit prea mare ecou in randul miscarii, probabil datorita faptului ca populatia Kitava studiata, avea cam multi carbo in dieta, ca sa fie pe gustul adeptilor obisnuiti cu sloganuri gen 60-70% grasime, keto, ultra low carb etc. Tot in 2010 apare o alta carte foarte influenta in randul comunitatii paleo The Paleo Solution: The Original Human Diet scrisa de Robb Wolf, un student de-al lui Cordain (care de altfel i-a scris prefata la carte). Considerat de multi urmasul lui Cordain, insa in ultima vreme relatiile s-au cam racit intre ei si in orice caz exista o diferenta de statura stiintifica evidenta intre cei doi. In 2010 apare o carte asteptata de cativa ani si care a atins statutul de cult The New Evolution Diet: What Our Paleolithic Ancestors Can Teach Us about Weight Loss, Fitness, and Aging scrisa de un economist Arthur De Vany, cu postfata scrisa de Nassim Nicholas Taleb (cel cu "Black swan"). In 2014 apare o carte sinteza The Paleo Manifesto: Ancient Wisdom for Lifelong Health scrisa de John Durant. In 2010 in The New York Times aparea un reportaj cu autorul ultimei carti, John Durant The New Age Cavemen and the City Este interesant de urmarit. Atmosfera ramasa in urma articolului este una incarcata de testosteron, te si intrebi cum isi pot gasi femeile un loc in aceste diete. Se pare totusi ca puterea marketingului a rezolvat aceasta dilema. Urmariti aceasta emisiune cu Dr Oz. Invitati Loren Cordain si Nell Stephenson aka Paleoista Cordain este creierul, Nell este imaginea, un binom imbatabil ! Daca cineva mai avea indoieli asupra puterii masinariei de marketing ! Ca sa apari la Dr Oz este deja o realizare in sine ! Care dintre femeile, care se lupta cu kilogramele in plus, si o priveste pe Nell si-l asculta pe Cordain, nu se lasa cucerita de acesta dieta? Cand Dr Oz o intreaba daca paleo este low carb, raspunde prompt ca nu este Atkins ! De parca asta i-ar strica reputatia ! Este interesant ca Loren Cordain alege o femeie ca sa-si promoveze cartile, produsele, si nu pe fostul sau student Robb Wolf. Si-a gasit aceasta nisa, a femeilor, care traditional au fost lasate pe dinafara in ceea ce priveste dieta paleo, si a ocupat-o rapid. Nici fostul sau student nu s-a lasat mai prejos si a promovat si el cateva doamne pe scena tot mai aglomerata a dietelor paleo. Cateva reprezentante la sexului frumos pe scena paleo: Nell Stephenson Paleoista: Gain Energy, Get Lean, and Feel Fabulous With the Diet You Were Born to Eat Diane Sanfilippo Practical Paleo: A Customized Approach to Health and a Whole-Foods Lifestyle prefata de Robb Wolf Sarah Fragoso Everyday Paleo introducere semnata de Robb Wolf Sarah Ballantyne The Paleo Approach: Reverse Autoimmune Disease and Heal Your Body prefata de Robb Wolf Melissa Hartwig It Starts With Food: Discover the Whole30 and Change Your Life in Unexpected Ways Catherine Shanahan Deep Nutrition: Why Your Genes Need Traditional Food Nora T. Gedgaudas Primal Body, Primal Mind: Beyond the Paleo Diet for Total Health and a Longer Life Dupa cum observati de numele lui Robb Wolf se leaga lansarea mai multor carti, de fapt nu vorbim de simple carti, in spatele lor stau bloguri, emisiuni de radio, acordarea de consultanta, participarea la conferinte, toate acestea pe bani, evident. Odata cu aceste carti se lanseaza adevarate afaceri. Este un model de business pe care-l observ de cativa ani. Se incepe timid cu un blog, se castiga ceva audienta, urmeaza participarea la emisiuni, podcasturi, la un nivel mai mare, de obicei la veterani din miscare, creste audienta, apar propriile podcaturi, emisiuni, se ajunge la propria carte, promovata la cei cu greutate din miscare, se ajunge la consultanta si luarea sub aripa a altor juniori si modelul se repeta. In toate aceste etape se dau si se fac bani. Totul a ajuns un business. Si unde sunt bani sunt si divergente. Lumea se astepta la un binom Cordain - Wolf, profesorul si studentul, insa fiecare a mers pe drumul lui. Cordain ajuns deja la o varsta cand nu prea mai era vandabil, il cam incurca pe Wolf, care a preferat sa mearga pe cont propriu sau sa fie mentorul altora si sa nu fie un simplu protejat. Cordain la randul sau a gasit o figura mai tanara si mai vandabila care sa-l mentina in joc. Fiecare are propria linie de produse paleo si protejati prin intermediul carora isi vand si ii ajuta la randul lor sa-si vanda produsele. In aceste circumstante cand totul a ajuns o mare afacere, ma intreb cine mai are interesul sa ofere informatii de mare acuratete sau cine are curajul sa recunoasca erori sau lipsuri in documentare sau pur si simplu sa faca update-uri la zi a acestor carti, cand acestea le-ar contrazice tezele sustinute? Si-ar taia singuri craca de sub picioare? Ma indoiesc ! Apare aici un conflict de interese care este incompatibil cu cunoasterea stiintifica ! Cine mai are garantia ca lucrurile stau asa cum le prezinta in aceste carti cand toata lumea alearga dupa bani? Despre divergentele aparute intre aceste grupari, intr-o postare viitoare ! |
#46
Posted 11 February 2015 - 20:59
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Am sa relatez cateva dintre divergentele din cadrul miscarii paleo sau dintr-un cadru mai larg al miscarii low carb. Aceasta relatare nu este una exhaustiva, ci doar o mica selectie dintr-un noian de contradictii, neconcordante sau interese divergente din cadrul acestor miscari. Uneori contradictiile sunt intre propriile afirmatii ale acestor guru sau intre afirmatiile acestora si sursele stiintifice pe care ei sustin ca se bazeaza.
Am sa incep cu Mark Sisson de la MarksDailyApple.com. Este un veteran al miscarii, desi prima sa carte dateaza doar din 2010. Blogul sau insa are o vechime mai mare (2006) si pe de alta parte varsta i se potriveste pentru aceast calificativ. Insa nu varsta este elementul determinant, ci faptul ca a scris una dintre primele carti care a dat nastere miscarii paleo. Desi carti despre dieta paleo s-au scris cu mult inainte de 2010, circumstantele au facut ca nasterea acestei miscari sa coincida cu aparitia cartii sale The primal blueprint. Se remarca si folosirea unei marci personale "primal" diferite de restul miscarii care foloseste expresia "paleo". Sisson este cea mai buna imagine pentru promovarea propriei diete, a cartilor sale, a liniei de suplimente, a orelor de consultanta, a intregii sale afaceri. Sa ai un abdomen "cu patratele" la varsta lui, reprezinta cea mai buna reclama. Sisson este o persoana foarte activa si adeptul a unui stil de viata in care sportul joaca un rol important. Recunoaste, de asemenea, importanta caloriilor, in sensul ca nu se poate slabi fara un deficit caloric, spre deosebire de multi care nu recunosc acest lucru. Despe importanta sportului, a efortului fizic in general iata ce parere are: PRIMAL BLUEPRINT FITNESS Quote Lift Heavy Things Resistance training is the cornerstone of fitness. Stronger people live longer, survive hardships better and are able to enjoy life more fully than weaker people. Two to three Lift Heavy Things workouts of 7-30 minutes each week, employing the Four Essential Movements (see below), are recommended. Run Really Fast Every Once in Awhile Sprinting is the biggest “bang for your buck” exercise. It’s brutally effective and highly efficient, promoting growth hormone release, fat burning and lean mass building. But you know why we really like sprinting? It’s over in 10 to 15 minutes… and you only have to sprint once a week! Move Frequently at a Slow Pace Slow movement is the foundation of fitness. Walking, hiking, gentle cycling—these activities aren’t about burning calories; they’re about maintaining the movement and the ability to move. Three to five hours of slow-paced movement a week is recommended. Deci miscare din plin! Ia sa vedem ce parere are Gary Taubes despre asta in Good calories, bad calories pag. 269: "When we are physically active, we work up an appetite. Hunger increases in proportion to the calories we expend, just as restricting the calories in our diet will leave us hungry until we eventually make good the deficit, if not more. The evidence suggests that this is true for both the fat and the lean. It is one of the fundamental observations we have to explain if we’re to understand why we gain weight and how to lose it." Concluzia lui Taubes este ca efortul fizic determina aparitia foamei, care determina un exces caloric care compenseaza caloriille pierdute prin efortul fizic, ba chiar existand riscul ingrasarii. Ideea asta nebuneasca este adoptata in unele cercuri low carb, insa in cele paleo este considerata controversata, nefiind de mirare citind ce scrie Sisson. Astfel de idei se bat cap in cap si dau nastere la confuzie in cercurile low carb paleo. O alta controversa exista in ceea ce priveste consumul de cartofi in dietele paleo. Sa-i dam cuvantul lui Loren Cordain: Are Potatoes Paleo? Quote Because potatoes maintain one of the highest glycemic index values of any food, they cause our blood sugar levels to rapidly rise which in turn cause our blood insulin concentrations to simultaneously increase. When these two metabolic responses occur repeatedly over just the course of a week or two, we start to become insulin resistant – a condition that frequently precedes the development a series of diseases known as the Metabolic Syndrome. Over the course of months and years, insulin resistance leads to a multitude of devastating health effects. The list of Metabolic Syndrome diseases is long: obesity, type 2 diabetes, cardiovascular disease, high blood pressure, high blood cholesterol and other abnormal blood chemistries, systemic inflammation, gout, acne, acanthosis nigricans (a skin disorder), skin tags, and breast, colon and prostate cancers. Potatoes contain two glycoalkaloid saponins: 1) α-chaconine and α-solanine which may adversely affect intestinal permeability and aggravate inflammatory bowel diseases (ulcerative colitis, Crohn’s disease and irritable bowel syndrome). Even in healthy normal adults a meal of mashed potatoes results in the rapid appearance of both α-chaconine and α-solanine in the bloodstream. I believe that far more troubling than the toxicity of potato glycoalkaloids is their potential to increase intestinal permeability over the course of a lifetime, most particularly in people with diseases of chronic inflammation (cancer, autoimmune disease, cardiovascular disease and diseases of insulin resistance). Many scientists now believe that a leaky gut may represent a nearly universal trigger for autoimmune diseases. A final note on potatoes to add insult to injury, this commonly consumed food is a major source of dietary lectins. On average potatoes contain 65 mg of potato lectin per kilogram. As is the case with most lectins, they have been poorly studied in humans, so we really don t have conclusive information how potato lectin may impact human health. However, preliminary tissue studies indicate that potato lectin resists degradation by gut enzymes, bypasses the intestinal barrier and can then bind various tissues in our bodies. Potato lectins have been found to irritate the immune system and produce symptoms of food hypersensitivity in allergenic and non-allergenic patients. Dupa descrierea lui Cordain se pare ca alimentul preferat al Diavolului este cartoful ! Dar ce zice Sisson? Quote A good chunk of this country, and indeed the entire world, is overweight. This is a problem. This is a problem that s growing, quite literally and figuratively. And they may not have gotten overweight in the first place because of baked sweet potatoes with grass-fed butter, or Yukon golds roasted in duck fat, but those foods certainly aren t going to help their current insulin-resistant predicament. Potatoes should be limited, or even outright eliminated, for this (large) subset of the population. For the lean and active, however, I don t think a few red potatoes with dinner are anything to worry about. Deci pana la urma cartofii nu sunt chiar asa de rai, cel putin pentru cei cu greutate normala. Pe cine sa crezi? Pe Cordain pentru care cartofii sunt toxici si trebuie eliminati din dieta sau pe Sisson care-i accepta in anumite conditii? Dar ce zice fostul student al lui Cordain, Rob Wolf? Meat & Potatoes: Back on the Menu Quote Meat and potatoes is probably the most Paleo of all meals. While the men were out hunting the women were gathering. What were they gathering? More often than not, tubers. For the most part, fruits, nuts, and seeds are targets of seasonal opportunity. Because it s a plant s long term storage organ, tubers are always around. They can and did form the backbone of many hunter/gatherer diets. It was this high nutrient density diet based on meat and tubers that made humans the high energy, big-brained masters-of-our-domain that we are today. It s our heritage and it s time we (re)embraced it. La fel ca si Sisson, Wolf accepta cartofii in dietele paleo pentru cei cu greutate normala, insa merge chiar mai departe sustinand ca ei reprezinta de fapt un aliment paleo pe care am evoluat sa-l consumam si pentru care suntem adaptati ! O diferenta de la cer la pamant intre Cordain si Wolf ! Pe cine sa crezi? Sisson in cartea sa The primal blueprint a detaliat cantitatile de carbohidrati permise in dieta paleo, mentionand 150 g/zi drept limita maxima admisa. Peste aceasta limita se produce ingrasarea. Evident ca aceasta limita este una fantezista, izvorata din inchipuirea lui Sisson, in nici un studiu despre dietele paleo nu se mentioneaza o asemenea limita ridicola, insa Sisson insista ca aceasta limita e "paleo": The Primal Blueprint Carbohydrate Curve Quote 150-300 grams/day – Steady, Insidious Weight Gain Continued higher insulin-stimulating effect prevents efficient fat burning and contributes to widespread chronic disease conditions. This range – irresponsibly recommended by the USDA and other diet authorities – can lead to the statistical US average gain of 1.5 pounds of fat per year for forty years.
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9 downloadsInsa intr-un alt articol se lauda ca studiile pe dieta paleo ii sustin lui opiniile: I’m Not Going to Say, “I Told You So” Este studiul lui Frassetto (studiul cu nr. 4 in cronologia facuta de mine intr-una din postarile anterioare). Insa in acel studiu carbohidratii au constituit 38% din dieta, 249 g/zi. Cum ramane cu carbohidratii peste 150 g/zi care determina "Steady, Insidious Weight Gain"? In cadrul comunitatii paleo nu se pot pune de acord nici macar asupra consumului de fructe si legume. De la aceasta postare care pretinde ca legumele iti distrug DNA-ul Vegetables damage your DNA pana la Sisson care le gaseste utilitatea Do You Really Need to Eat Vegetables to Be Healthy? si pana la raspunsul furios al acestei adepte paleo care le gaseste inutile, daca nu de-a dreptul toxice Response to Mark Sisson's assertion that vegetables are necessary for health Pe cine sa crezi? Dar cerealele, cum sunt ele vazute de catre cercurile paleo, low carb? Rau, foarte rau ! In viziunea lor cerealele sunt toxice, cauzeaza inflamatie, boli autoimune, sunt ucigase de-a dreptul ! O postare la intamplare de pe blogul Melissei Hartwig The Grain Manifesto Quote Our general nutritional recommendations don’t include grains of any kind—no breads, cereals, pasta, rice, not even gluten-free grains or pseudo-cereal. No, not even whole grains.* While grains are technically seeds of plants in the grass family, for our purposes we’re going to lump similarly-structured pseudo-cereals in this category as well. This list includes wheat, oats, barley, rye, millet, corn (maize), rice (including wild rice), sorghum, teff, triticale, spelt, kamut, buckwheat, amaranth, and quinoa. *Note, we are well aware that this information may run counter to everything you’ve ever been told by your parents, doctors, personal trainers, government agencies and TV advertisements. For that, however, we make no apologies… because all the people who have been selling you Whole Grains for Health all these years have been just. Plain. Wrong. We understand if this makes you kind of angry. It makes us angry too.. but that’s a topic for another post. What About Soaking, Sprouting, and Fermenting? Ancient cultures reliant on grains for survival figured out ways to prepare them to mitigate some of the inflammatory and anti-nutrient downsides. Prolonged soaking, extended cooking, rinsing, sprouting, and fermenting have been shown to partly break down some of the phytates and some of the inflammatory proteins in certain grains. But note the words “partly” and “some.” These preparation methods don’t guarantee a safe food product in your gut, and vegetables and fruit still provide far more nutritious benefits with none of the downsides of grains. Weston A. Price Foundation nici nu vrea sa auda asa ceva. Pentru ei cerealele sunt ok, cu conditia prepararii lor corespunzatoare (inmuiere, fermentare, incoltire). Bread–A Modern Curse? Quote According to recent news articles, celiac disease–the inability to digest certain proteins in gluten-containing grains such as wheat, rye, barley and oats–afflicts at least one in 30 people. So common and so debilitating is this malady that many popular nutrition doctors and nutrition writers forbid the consumption of grains as a matter of course. In The Paleo Diet, for example, author Loren Cordain blames the consumption of grains for our modern deficiency diseases, and the narrowing of the jaw so prevalent in modern humans. According to Barry Sears, PhD, author of The Zone Diet, the switch to a grain-based diet in Egypt was a chief factor in the emergence of the diseases of modern civilization. Dr. Joe Mercola tells his patients to avoid grain, period. Yet Weston Price studied several societies that enjoyed remarkable good health even though they consumed grains as a principle foodstuff. The primitive Swiss of the Loetschental Valley baked a sourdough bread in communal ovens, made of locally grown rye ground fresh in a stone mill. Rye bread plus rich dairy products–milk, butter and cheese–were the chief articles of the diet. Likewise, the primitive Gaelic peoples subsisted on seafood and oats. Both these groups exhibited beautiful facial structure and were free of deficiency diseases. Price also found healthy groups in Africa and South America that consumed large quantities of grain, usually as a sour fermented porridge or beverage. Connfuzia pare sa fie o stare de fapt in comunitatea paleo/low carb. Dar WAPF nu se opreste aici, face praf si cartea lui Rob Wolf "The Paleo Solution", care este protejatul lui Cordain, acesta din urma semnand prefata cartii. Se pare ca dieta aceasta paleo este prea saraca in grasimi animale, pentru gustul urmasilor lui Price. Quote This diet is low in carbs, low in saturated fat, and high in protein, with protein comprising up to 30-35 percent of calories. “Protein consumption beyond this point for extended period of time,” he says, “results in a condition called rabbit starvation,. . .. a disease characterized by muscle wasting, lethargy, diarrhea and eventually death if one relied too heavily on lean game animals such as rabbits.” But Wolf’s diet does precisely that―it leans heavily on lean animals, domestic animals, to be sure, but nevertheless lean. This book is all about lean, lean, lean―just a teaspoon or two of olive oil for cooking, no butter on the vegetables, no sauces on those large portions of lean meat. Wolf s paleo diet poses two major dangers. First, the high protein content, along with vitamin D supplements (recommended to provide 2-5,000 IU vitamin D per day) can rapidly deplete vitamin A. When vitamin A is depleted, we are vulnerable to all sorts of medical conditions, particularly autoimmune disease. Wolf sees autoimmune disease as a widespread problem without appreciating the irony of vitamin A deficiency brought on by a diet too high in protein and vitaimn D. The second danger is a deficiency of saturated fat. Our bodies need saturated fat in large amounts to build cell membranes for one thing (which need to be at least 50 percent saturated to work properly) and to support hormone formation and the immune system. The fats in Wolf s diet are mostly monounsaturated, with saturated fats comprising a measly 18 grams (just over 1 tablespoon) per day. When we do not get enough saturated fat in the diet, the body can make these from carbohydrates but carbs are not allowed in the diet either. The result is either severe deficiency in saturated fat (for those with will power to stay on the diet) or bingeing and splurging on refined carbs and foods rich in saturated fat, like chocolate and ice cream. Acest atac pune la indoiala nu numai cartea lui Wolf, dar si pe a lui Cordain (fiind similara in principiile sustinute cu a lui Wolf) si in general dieta paleo. Avand in vedere influenta acestei fundatii in lumea low carb/paleo, ce poate sa fie in mintea unui nou venit in lumea paleo citind aceste lucruri care se bat cap in cap? Confuzie maxima ! Dar WAPF continua atacul si asupra noii mode ce prinde din ce in ce mai mult in cercurile paleo: intermitent fasting. The Warrior Diet by Ori Hofmekler Quote Hofmekler says his diet will work without the workout, but it is unclear how his method of eating is terribly different from calorie restriction, or simply eating more healthy, nutrient-dense food. While his method could benefit an overweight, but otherwise healthy person, it could mean trouble for someone with unstable blood sugar, or a family history of diabetes. He correctly states that during fasting, insulin levels go down and growth hormone is released. But he incorrectly states that insulin resistance is reduced during fasting, when in fact, numerous studies show that fasting increases insulin resistance. Din nou contradictii peste contradictii. Dar, probabil cea mai mare lovitura pe care a suferit-o atat comunitatea low carb cat si cea paleo, a fost aparitia in 2010 a cartii The perfect healt diet Ideea de baza a acestei carti este ca glucidele sunt nutrienti importanti si necesari in dieta umana. Propune conceptul de "safe starches", intelegand prin asta orez, cartofi, taro etc. Desi pastreaza modelul unei diete high fat, se departeaza de modelul low carb, propunand un nivel mai ridicat al carbohidratilior in diata. Structura dietei arata cam asa: in jur de 450 g/zi de fructe, morcovi, sfecla; 450 g/zi cartofi, orez, taro; legume la liber; leguminoase precum mazarea sau fasolea verde; se recomanda evitarea cerealelor, zaharului si limitarea grasimilor PUFA. Dieta a produs unde de soc in comunitate si autorul cartii a fost invitat in emisiunea lui Jimmy Moore Pentru cine n-a auzit de acesta din urma, ar trebui sa stie ca este un fel de "axis mundi" in lumea low carb/paleo. Practic prin emisiunea lui (aproape 1000 de podcast-uri) au trecut mai toti cei care reprezinta ceva in comunitatea low carb/paleo, de la Mark Sisson la Gary Taubes si de la Michael Eades la Joseph Mercola. In urma emisiunii Jimmy Moore a chemat "brigada", adica o serie de lideri marcanti ai gruparii care sa combata "erezia". Reactiile au fost de la "e cea mai mare prostie pe care am auzit-o" venind dinspre fundatia Atkins, pana la "evident ca autorii n-au auzit de indicele glicemic" venind dinspre Cordain sau chiar invocarea acestei diete drept periculoase de catre Richard Feinman, insa au fost si reactii pozitive. Cititi postarea si minunati-va. Autorii cartii au raspuns tot intr-o lunga postare tuturor criticilor. Instructiv de citit, pentru ca in acele vremuri s-au batut cuiele in cosciugul teoriei lui Gary Taubes, s-a desfiintat ideea repetata ca o mantra in comunitate ca "nu exista asa ceva precum carbohidrati esentiali". Si totul a pornit din interiorul comunitatii ! Lucrurile au luat o turnura urata si cand unul din cei mai influenti oameni din miscarea paleo a "defectat". Practic a recunoscut ca teoria asta cu insulina e o prostie, ca daca manaci multa grasime fara sa tii seama de calorii o sa te ingrasi, ca in cele din urma caloriile conteaza, ca nu e suficient sa tai carbohidratii ca sa slabesti, ca reductia glucidelor foloseste celor cu rezistenta la insulina, insa celor sanatosi nu etc. Quote Where once I was doing several sports, running a gym, and running around like a mad-man, eventually I found myself more and more sedentary (writing stuff for the blog, doing the book, and traveling), and I had a tough time remaining lean. I’d cut carbs…but to no effect on body composition. Slowly I realized, both by experimentation and by really looking at the literature: CALORIES MATTERED MORE THAN CARBS FOR BODY-COMP. I have to say this was a pretty big shake-up for me. I’d assumed one could eat as much fat as one desired and STILL get leaner. As I mentioned above, when I first started eating LC, or more specifically, cyclic low carb (CLC) I was leaner than ever in my life. I know based on blood work and fat deposition that I had insulin resistance while vegan, and CLC helped with this immensely, but it was my new-found energy and activity level that drove my leanness, not an inability to store fat in the absence of significant insulin. I think this is one of the most damaging messages that comes out of the LC camp to this day, I was duped by this, so I’m not going to do what a lot of other recovered LC writers do and make folks out to be idiots for still believing this…but, it is time to face facts. In every damn study it is clear that for fat loss we’d like adequate protein, and a calorie restriction scenario. LC is fantastic for this in that one typically feels satisfied on high protein, moderate fat, loads of veggies. If one is insulin resistant, this approach can be nothing short of miraculous. HOWEVER! If one manages to cram enough cheese, olive oil and grass-fed butter down the pie-hole, this is in fact, a “mass gain” diet. The insistence on the part of the LC community in adhering to the no insulin, no fat gain dogma ends up discrediting the real therapeutic benefit of LC and hurts us all. The insulin resistant, crack-addicted individual really benefits from LC, I cannot say that sufficiently, and the ease with which people lose weight (fat) on these programs is remarkable, but insulin control takes a backseat to calorie reduction via highly satiating foods. This whole situation further damages the ability to push ketosis as a therapeutic treatment for everything from cancer to neurodegenerative disease. It s a tool folks, not en end all-be-all. In concluzie, exista un talmes-balmes de idei in comunitatea low carb/paleo. O afirmatie dintr-o carte este contrazisa de alta din alta carte, nu se pot decela un set comun de idei, principii pe care sa se bazeze aceasta/aceste diete, nu se pot hotari ce dauneaza si ce este benefic, nu se pot trasa limite, nici in cadrul dietei paleo si nici in cadrul mai larg al dietelor low carb. Ce este paleo pana la urma? Este laptele paleo? Sunt cerealele paleo ? Sunt leguminoasele paleo ? Sunt cartofii paleo ? Este orezul paleo ? SUnt carbohidratii daunatori ? Efortul fizic cauzeaza foame si trebuie evitat, caci altfel duce la ingrasare ? CAre sunt limitele de demarcatie ale dietei paleo: socotind de acum 2.5 mil ani ? De ce nu ne ducem mai inapoi, acum 20 mil. ani ? Genomul a fost influentat doar de acum 2.5 mil. ani, cand am inceput sa consumam carne, dar cei aproape 15 mil. ani cand dieta era frugivora, n-au contat, n-au modelat si ei genomul uman ? Aproape toata carnea consumata azi provine de la animale domestice, cu un profil a lipidelor net diferit de cel animalelor salbatice. Majoritatea legumelor si fructelor consumate astazi n-au existat in paleolitic, sunt rezultatul erei agricole. Pana la urma ce este paleo ? Nu se iluzioneaza cei care care consuma alimentele lumii moderne (carnea si fructele si legumele) cand cred ca ei consuma o dieta paleo ? (oricare ar fi aceea ?) La final cateva poze cu Mark Sisson din tinerete, cand era maratonist si consuma peste 1000 g carbohidrati pe zi si avea 8% body fat. Body Composition Through the Years Va recomand sa urmariti si acest material interesant despre ce inseamna/nu inseamna dieta paleo ! Debunking the paleo diet |
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#47
Posted 16 February 2015 - 18:29
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Cand am inceput sa scriu pe acest forum, una din primele replici pe care le-am auzit in favoarea regimurilor low carb, a fost aceea ca, deoarece grasimea reprezinta cea mai mare resursa enegetica a corpului nostru, asta inseamna ca dieta noastra trebuie sa se bazeze pe grasime. Marturisesc ca mi-a fost dificil sa inteleg logica acestui rationament, insa m-a facut sa ma gandesc la urmatoarele lucruri:
-de ce depozitam cea mai mare parte a energiei sub forma de grasime? -de ce nu depozitam energia in cea mai mare parte sub forma de glicogen? -care este ordinea oxidarii macronutrientilor din dieta? Am sa pornesc, in sustinerea mea, de la cateva observatii: -glucidele au cam 4 Cal/g -proteinele au in jur de 4 Cal/g -alcoolul are aprox. 7 Cal/g -grasimile furnizeaza cam 9 Cal/g -1 g de glicogen este stocat impreuna cu 2-4 g de apa -1 g grasime este stocat impreuna cu 0.15 g de apa Pe parcursul evolutiei noastre, selectia naturala a facut ca cei mai adaptati mediului sa supravietuiasca si sa-si transmita genele mai departe. Fie prin selectia sexuala, fie prin mutatii genetice intamplatoare, anumiti indivizi au capatat anumite caracteristici genetice care i-au facut mai bine adaptati supravietuirii intr-un anumit mediu si la numite conditii de viata. Ei au supravietuit si au transmis acele gene mai departe, pe cand ceilalti mai putin adaptati au avut o sansa mai redusa de supravietuire si linia lor genetica s-a transmis intr-o masura mai mica. Cu siguranta ca una din caracteristicele foarte importante de-a lungul evolutiei, a fost aceea de a putea acumula cu usurinta un exces de energie care sa poata sa fie folosit in timpul periodelor de foamete sau cand resursele erau foarte limitate. Indivizii cu aceste caracteristici au supravietuit si au transmis mai departe aceasta mostenire genetica, insa ceilalti care erau rezistenti la acasta acumulare de energie au avut sanse mai mici de supravietuire, intrucat resursele lor limitate se terminau inaintea celorlalti, prin urmare si zestrea lor genetica nu mai apuca sa fie transmisa mai departe. Persoanele care astazi se ingrasa foarte usor au fost norocosii acelor vremuri, iar cei care se ingrasa greu in zilele noastre au fost fost cei mai putin norocosi atunci. De aceea astazi sunt mai numerosi cei cu tendinta de ingrasare, sunt aceia care au fost mai bine adaptati si au supravietuit, iar minoritarii sunt cei care sunt rezistenti la ingrasare, adica cei care au avut o sansa mai redusa de supravietuire si de aceea si-au transmis genele intr-un numar mai mic. In zilele noastre, datorita abundentei resurselor alimentare, acei norocosi ai vremurilor trecute, datorita usurintei cu care acumuleaza excesul de energie au devenit ghnionistii lumii moderne, iar aceia care abia au supravietuit acelor vremuri au devenit cei feriti de obezitate si de bolile lumii moderne asociate acesteia. Acum sa vedem de ce totusi evolutia a favorizat acumularea acelui exces de energie sub forma de grasime si nu sub forma de glicogen. Ce s-a intamplat in corpul uman, atunci cand s-au consumat concomitent si carbohidrati si grasimi. Din punct de vedere fizilogic au fost favorizate acele mecanisme capabile sa ofere un avantaj de supavietuire. In acesata privinta corpul uman s-a vazut in fata urmatoarei dileme: sa foloseasca carbohidratii si sa depoziteze grasimile sau sa foloseasca grasimile si sa depoziteze carbohidratii. Este evident ca evolutia a preferat prima situatie. Dar de ce? Pentru ca acest lucru a insemnat un avantaj metabolic, concretizat intr-un avantaj de adaptare si supravietuire. Corpul prefera sa stocheze excesul de energie sub forma de grasime, pentru ca la masa egala grasimea furnizeaza mai multa energie, vitala in caz de lipsa de resurse. 1 kg de glicogen ar fi furnizat 4000 de Cal, pe cand 1 kg de grasime furnizeaza 7700 de Cal (grasimea este stocata in tesutul adipos cu putina apa, 1 kg de tesut adipos are 85-86 % grasime pura si 14-15 % apa). Un al doilea avantaj il reprezinta greutatea redusa al stocarii sub forma de grasime. 1 kg de grasime pura necesita in jur de 150-160 g de apa, deci cam 1160 g in total, furnizand 9000 Cal. pentru supravietuire. 1 kg de glicogen ar fi necesitat intre 2-4 kg de apa pentru stocare, deci intre 3-5 kg in total, furnizand doar 4000 Cal, ceea ce ar fi scazut in mod substantial sansele de supravietuire, din cauza aportului mai mic de energie si din cauza greutatii suplimentare al acestui tip de stocare, care ar fi ingreunat si deplasarea, dar ar fi crescut si necesarul energetic pentru acest bagaj suplimentar. Iata de ce evolutia a favorizat depunerea excesului de energie sub forma de grasime (prin exces intelegand excesul de orice fel, proteine, glucide, lipide, dar mai ales pe acestea din urma). Un al treilea motiv pentru care lipidele in exces sunt transformate in tesut adipos, mai usor chiar decat excesul de glucide, il constituie costul mai mic de stocare per unitate de lipide (5-10 %), fata de costul mai ridicat al stocarii glucidelor sub forma de lipide (15-25 %). Pur si simplu se pierde mai putina energie cu stocarea lipidelor din alimentatie in exces, decat cu stocarea excesului de glucide (acestea trebuie sa treaca prin transformari succesive pentru a ajunge sub forma de trigliceride), acest lucru asigurand un avantaj de supravietuire. Este evident ca fiind preferata grasimea ca forma de stocare a excesului, raman carbohidratii ca sursa primara de energie. Trebuie precizat ca intr-o dieta normala dpdv caloric, grasimile din dieta nu ingrasa in sensul unui aport definitiv la tesutul adipos, ci doar al unui aport temporar, asta pentru soarta majoritatii grasimilor din dieta, dupa ingerare, este incorporarea in tesutul adipos. Nu exista nici o zona tampon semnificativa, in care lipidele sa fie deversate, in afara tesutului adipos. Nu se pot depune semnificativ nici in ficat, nici in muschi, ci doar in tesutul adipos. Asta nu inseamna ca ele vor ramane acolo, ci vor fi eliberate pe parcusul zilei si mai ales pe parcursul noptii si oxidate, insa arata usurinta cu care ele sunt depuse in tesutul adipos. Spre deosebire, carbohidratii din dieta imediat dupa ingerare, urmeaza o alta soarta. Intr-o prima faza creste oxidarea lor (transformarea in energie), apoi urmeaza stocarea lor in ficat si muschi sub forma de glicogen. In caz de exces caloric carbohidratii nu sunt transformati in grasime pana nu sunt saturate depozitele de glicogen. Proteinele sunt folosite pentru satisfacerea nevoilor structurale ale organismului (tesut muscular, hormoni, enzime, neurotransmitatori etc), in caz de deficit caloric ele pot fi folosite drept combustibil. Alcoolul este degradat pentru a se inlatura compusii toxici si in acest proces se genereaza energie. Ordinea in care sunt oxidati acesti nutrienti: alcoolul este prioritar pentru ca este toxic si trebuie eliminat rapid, carbohidratii si proteinele urmeaza, primii furnizand energie si proteinele indeplinind un rol structural, grasimile sunt si ele folosite intr-o mica masura pentru nevoile imediate de energie, insa cea mai mare parte iau drumul tesutului adipos. Exista un ciclu neintrerupt de producere, stocare si reciclare a combustibililor in organism. De pilda tesutul adipos elibereaza acizi grasi care intra in circuitul sanguin, sunt extrasi de acolo de celule, tesuturi, organe pentru nevoile lor energetice, restul sunt reesterificati in trigliceride si ajung in tesutul adipos, apoi ciclul se reia. Glucoza este produsa prin gluconeogeneza, este folosita de organe, tesuturi, produsii secundari precum piruvatul si lactatul sunt reciclati in ficat, unde se produce din nou glucoza si ciclul se reia. Dupa o masa bogata in carbohidrati, creste glicemia, se elibereaza insulina care are urmatoarele efecte: -stimuleaza secretia de LPL (lipoprotein lipaza) -stimuleaza lipogeneza -stimuleaza glicogeneza -stimuleaza glicoliza -stimuleaza absorbtia de lipide, proteine si glucide de catre tesuturi -inhiba HSL (human sensitive lipase) -inhiba lipoliza -inhiba glicogenoliza -inhiba gluconeogeneza Explicatie: cand in sange este prezent din abundenta un combustibil (glucoza), corpul n-are nici un motiv sa mai foloseasca celalalt combustibil (acizii grasi), de aceea inhiba eliberarea de acizi grasi din tesutul adipos si stimuleaza incorporarea celor existenti (din dieta sau eliberati anterior din tesutul adipos) in tesutul gras. De aceea stimuleaza LPL care are rolul de desface trigliceridele in acizi grasi, pentru ca ei sa poata patrunde in celulele adipoase si inhiba HSL care are rolul de a desface trigliceridele din tesutul gras. Pentru ca este o abundenta de glucoza, corpul stimuleaza arderea ei (glicoliza) si de asemenea stimuleaza depunerea ei sub forma de glicogen (glicogeneza). Pe de alta parte nemaiavand nevoie de combustibil suplimentar, inhiba eliberarea de acizi grasi (lipoliza), inhiba formarea de combustibil nou (gluconeogeneza) si inhiba de asemenea si eliberarea de combustibil existent (glicogenoliza, adica desfacerea glicogenului pentru a forma glucoza). Dupa cum se observa corpul are o logica a lui, care se circumscrie unei functionari rationale si nu este nimic anormal sau daunator in efectele insulinei, asa cum o prezinta Gary Taubes. Ce trebuie retinut este ca, in ciuda ideilor propagate de Taubes & Co, aceste efecte sunt limitate in timp, nu sunt permanente asa cum lasa acesta sa se inteleaga. De asemenea efectul inhibitor nu este absolut, ci chiar si asa ciclul de eliberare si resterificare continua, el nu se opreste niciodata, insa e adevarat la niveluri mult mai mici. Dar acest efect inhibitor actioneaza postprandial (adica dupa masa), in jur de 3 h, dupa care nivelul insulinei revine la normal si toate aceste cicluri de eliberare, oxidare si depozitare a acizilor grasi din si inspre tesutul adipos se reiau. La fel si cu glucoza. Practic daca calculam ca intre mese exista o fereastra de vreo 6 h, rezulta ca cel putin 6 h exista intre cele 3 mese principale, perioada in care insulina este la un nivel normal si oxidarea grasimilor continua fara probleme. Daca adaugam si perioada noptii in care se ard majoritar acizi grasi (8-10 h), rezulta o perioada suficient de mare pentru oxidarea grasimilor. La toate acestea se adauga faptul ca in final procesul de slabire si ingrasare este guvernat de legile fizicii, de necesarul si de cheltuiala energetica a organismului. Acum sa vedem cum functioneaza bizara logica a celor care neaga caracterul stiintific al teoriei balantei calorice. Taubes este atat de confuz in cartile sale incat afirma intr-o parte ca aceasta este adevarata, iar in alta parte ca nu conteaza, doar carbohidratii conteaza. Sa presupunem ca o persoana are nevoie de 2500 Cal /zi si urmeaza o dieta hipocalorica de 2000 de Cal/zi, dar high carb 60%. Respectiva persoana are un deficit de 500 Cal/zi, conform teoriei ea va slabi, insa conform lui Taubes ea se va ingrasa. Intrebare de unde provine excesul necesar ingrasarii cand persoana este in deficit? Se creeaza energie din nimic ? E ca si cum ai avea o plasa de 2 kg de cartofi, scoti unul si plasa va cantari 3 kg. E absurd ! Se incalca prima lege a termodinamicii ! Sa presupunem acum ca o persoana consuma o dieta high fat 60%, de 3000 de Cal/zi, cu 500 de Cal peste nevoile sale zilnice. Conform teoriei se va ingrasa, conform lui Taubes ea va slabi, pentru ca nu este stimulata insulina si acizii grasi vor fi mobilizati din tesutul adipos. Cum se produce deficitul in conditiile in care in corp intra mai multe calorii decat ies? E ca si cum ai avea o plasa de cartofi de 2 kg, mai adaugi un kg si plasa va cantari 1 kg ! Dispare energia in neant ? Din nou absurd ! Dar despre Taubes si incercarile lui absurde de a ocoli legile fizicii, in postarea viitoare. |
#48
Posted 16 February 2015 - 19:16
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Excelentă logica și pe înțelesul maselor. Ai putea câștiga bani dacă ai scrie o carte (dacă nu ai deja una). Te felicit sincer pentru calitatea explicațiilor!
Ca temă viitoare de studiu, aș propune "intermittent fasting". Succes! |
#49
Posted 17 February 2015 - 08:30
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Logica e defecta, din pacate, rationamentul porneste de la premize gresite si e ingreunat de ideile preconcepute ale asa-zisului sceptic.
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#50
Posted 17 February 2015 - 10:45
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Toti avem idei preconcepute, nu e mereu bine, dar totuși, acestea pot fi corecte. Care crezi că ar fi premizele greșite de la care pleacă raționamentul de mai înainte?
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#51
Posted 17 February 2015 - 10:51
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Logica e defecta, din pacate, rationamentul porneste de la premize gresite si e ingreunat de ideile preconcepute ale asa-zisului sceptic. Greșește pentru că tu mănânci 4000 de calorii din grăsime și nu te îngrași?
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#52
Posted 17 February 2015 - 11:39
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Nu mananc 4000 kcal si nu ma ingras. Ma indoiesc ca asta spune Taubes, ca daca mananci LCHF, poti manca oricat si nu te ingrasi.
La fel, ma indoiesc ca Taubes spune ca sportul e nasol. El spune doar ca nu prin sport trebuie slabit, ci prin nutritie, altfel e chinuitor si nesanatos. Dar @scepticul interpreteaza cum vrea, ca sa-i iasa pasenta.
Toti avem idei preconcepute, nu e mereu bine, dar totuși, acestea pot fi corecte. Care crezi că ar fi premizele greșite de la care pleacă raționamentul de mai înainte? Cand mai si interpreteaza gresit principiile si apoi le demonteaza, ceva e putred. Dar e OK, da senzatia de semidoct, foloseste multi termeni pe care mai nimeni nu-i intelege, foloseste multe citate, multi o sa aiba impresia ca stie ce spune. |
#53
Posted 17 February 2015 - 11:42
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poti manca oricat si nu te ingrasi. Vezi, eu pe asta de mai sus o numesc idee preconcepută! Ce crezi că se întâmplă cu surplusul? Se elimină? |
#54
Posted 17 February 2015 - 11:47
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Pai nu sustine nimeni asa ceva, ai scos tu din context, exact cum face si @scepticul.
Eu zic ca nu poti manca oricat si sa nu te ingrasi, nici Taubes nu sustine asa ceva, iar tu tai nu-ul din fata si ma intrebi cum pot demonstra. WTF ?! Serios ma intrebi asta ?! Fiindca sunt siderat. |
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