The Paleolithic diet, also popularly referred to as the caveman diet, Stone Age diet and hunter-gatherer diet, is a modern nutritional plan based on the presumed ancient diet of wild plants and animals that various hominid species habitually consumed during the Paleolithic era—a period of about 2.5 million years duration that ended around 10,000 years ago with the development of agriculture. It is based upon everyday, modern foods that mimic the food groups eaten during prehistoric times. The diet became popular in the late 2000s, and was Google’s most searched-for weight loss method in 2013.
The diet is based on several premises, one of which is that human ancestors evolved for thousands of years and became well-adapted to foods of the Paleolithic era. Advocates argue that food cultivation and preparation greatly declined in quality about 10,000 years ago, with the advent of agriculture and domestication of animals and that humans have not evolved to properly digest new foods such as grain, legumes, and dairy, much less the highly-processed and high-calorie processed foods that are so readily available and cheap, and this has led to modern-day problems such as obesity, heart disease, and diabetes. Advocates claim that followers of the diet may enjoy a longer, healthier, more active life.
Critics of the diet point out that humans are much more adaptable than previously thought, that the hypothesis that they are genetically adapted to the Paleolithic environment is flawed, that it is in any case practically impossible for humans to know how their ancestors ate. Nutritionists have pointed out that the diet may be less effective than other popular diets in promoting good health.
- 1 History
- 2 Rationale for the diet
- 3 The diet
- 4 Reception
- 5 See also
- 6 References
An early book on the topic was The Stone Age Diet, self-published in 1975 by Walter Voegtlin. In 1985, Boyd Eaton and Melvin Konner published a paper on Paleolithic nutrition in the New England Journal of Medicine followed in 1988 by the book, with Marjorie Shostak, The Paleolithic Prescription. Since the late 1990s many others have published works promoting the diet, including Staffan Lindeberg, Mark Sisson, Arthur De Vany.
The diet was overshadowed by regimens such as the Atkins diet and South Beach Diet until the publication of a popular book by Loren Cordain. The latter is styled as "Dr Loren Cordain, world's leading expert on paleolithic diets and founder of The Paleo Movement". His doctoral degree was in exercise physiology, and he is the owner of the trademark "The Paleo Diet".
Rationale for the diet
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The rationale is that:
- Human physiology has changed little since the time our ancestors were hunter-gathers. Modern humans are adapted to the diet or diets of the Paleolithic period.
- The dawn of agriculture and industrialization has led to the availability of foods for which we are not evolutionarily adapted.
- It is possible to understand the ancient diet and reproduce it in modern times, and to learn from contemporary hunter-gatherers.
- Diet is at least in part to blame for diseases of affluence and lifestyle diseases, and that eaters of forager-style diets do not suffer from them.
Advocates of the diet argue the ancient diet was characterized as follows:
- No dairy food.
- Very little cereal grains.
- Food was not salted.
- Lean meat was eaten.
Criticism of the rationale
It has been argued that the notion of humans being unable to adapt to modern food is based on a flawed adaptationistic logic, and that modern people are adapted to modern foods, since most of the change in the frequencies of alleles occurs in the first few generations under selection. For example, research has shown that various populations which have domesticated cattle have independently developed alleles for dairy tolerance.
It is often argued that preagricultural foragers did not suffer from the diseases of affluence simply because they did not live long enough to develop them.
With regard to attempts to emulate the "ideal" diet, molecular biologist Marion Nestle argues that "knowledge of the relative proportions of animal and plant foods in the diets of early humans is circumstantial, incomplete, and debatable and there are insufficient data to identify the composition of a genetically determined optimal diet. The evidence related to Paleolithic diets is best interpreted as supporting the idea that diets based largely on plant foods promote health and longevity, at least under conditions of food abundance and physical activity". Ideas about Paleolithic diet and nutrition are at best hypothetical.
Trying to devise an ideal diet by studying contemporary hunter-gatherers is difficult because of the great disparities that exist, for example with the animal-derived calorie percentage ranging from 25% in the Gwi people of southern Africa to 99% in Alaskan Nunamiut.
Food energy excess, relative to energy expended, rather than the consumption of specific foods may underlie the diseases of affluence. Studies of traditionally living populations show that humans can live healthily with a wide variety of diets. We have evolved to be flexible eaters. "The health concerns of the industrial world, where calorie-packed foods are readily available, stem not from deviations from a specific diet but from an imbalance between the energy we consume and the energy we spend."
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. 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.
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. According to the United States Department of Agriculture, the acceptable macronutrient distribution range for carbohydrates is 45 to 65 percent of total calories. A typical modern diet gets a lot of carbohydrates from dairy products and grains, but these are excluded in the Paleolithic diet.
High fiber intake not via grains, but via non-starchy vegetables and fruits.
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 since saturated fats are considered to have little or no adverse effects upon cardiovascular disease risk.
It is well known that modern diets are high in salt and many diets, including the Paleolithic, recommend a reduction.
Balanced alkaline vs. acid
Any food presents either a net acid (e.g. meats, fish, grains, legumes, cheese, and salt) or alkaline (e.g. fruits and vegetables) load to the kidneys. A good diet strikes a balance.
A higher intake of vitamins and minerals is recommended via grass-fed meats, fruits, and vegetables rather than grains.
The Paleolithic diet has lower energy density than the typical diet consumed by modern humans. This is especially true in primarily plant-based/vegetarian versions of the diet, but it still holds if substantial amounts of meat are included. For example, most fruits and berries contain 0.4–0.8 calories per gram, and vegetables can be even lower than that (cucumbers contain only 0.16 calories per gram). Game meat, such as cooked wild rabbit, is more energy-dense (up to 1.7 calories per gram), but it does not constitute the bulk of the diet by mass or volume at the recommended plant/animal ratios, and it does not reach the caloric densities of many processed foods commonly consumed by modern humans: most McDonald's sandwiches such as the Big Mac average 9 calories per gram, since there is a high fat content and fat yields 9 cal/gram. and sweets such as cookies and chocolate bars commonly exceed 4 calories per gram.[original research?]
Diets with a low caloric density tend to provide a greater feeling of satiety at the same energy intake, and they have been shown effective at achieving weight loss in overweight individuals without explicit caloric restrictions.
Even some authors who may appear otherwise critical of the Paleolithic diet have argued that the high energy density of modern diets, as compared to ancestral or primate diets, contributes to the incidence of diseases of affluence in the industrial world.
Fruits, vegetables, meat and organ meats, and seafood, which are staples of the forager diet, are more micronutrient-dense than refined sugars, grains, vegetable oils, and dairy products in relation to digestible energy. Consequently, the vitamin and mineral content of Paleolithic diet is very high compared with a standard diet, in many cases a multiple of the RDA. Fish and seafood represent a particularly rich source of omega-3 fatty acids and other micronutrients, such as iodine, iron, zinc, copper, and selenium, that are crucial for proper brain function and development. Terrestrial animal foods, such as muscle, brain, bone marrow, thyroid gland, and other organs, also represent a primary source of these nutrients. Calcium-poor grains and legumes are excluded from the diet. However, leafy greens like kale and dandelion greens, as well as nuts like almonds, are very high sources of calcium. Moreover, components of plants make their low amounts of calcium much more easily absorbed, unlike items with high calcium content, such as dairy. Two notable exceptions are calcium and vitamin D, both of which may be present in the diet in inadequate quantities. Modern humans require much more vitamin D than foragers, because they do not get the same amount of exposure to sun. This need is commonly satisfied in developed countries by artificially fortifying dairy products with the vitamin. To avoid deficiency, a modern human on a forager diet would have to take artificial supplements of the vitamin, ensure adequate intake of some fatty fish, or increase the amount of exposure to sunlight (it has been estimated that 30 minutes of exposure to midday sun twice a week is adequate for most people).[original research?]
On the Paleolithic diet, practitioners are permitted to drink mainly water, and some advocates recommend tea as a healthy drink. Alcohol is not considered "paleo" as our ancestors could not produce drinks containing it; nor is coffee.
Raw vs. cooked
Unlike raw food diets, all foods may be cooked, without restrictions. However, there are Paleolithic dieters who believe that humans have not adapted to cooked foods since the first control of fire by Homo erectus, and so they eat only foods that are both raw and Paleolithic.
Food groups that advocates claim were rarely or never consumed by humans before the Neolithic agricultural revolution are excluded from the diet, mainly dairy products, grains, legumes (e.g., beans and peanuts), processed oils, refined sugar, and salt. Many of these foods would have been available at certain times of the year and may or may not have been consumed. Some advocates consider the use of oils with low omega-6/omega-3 ratios, such as olive oil, to be healthy and advisable.[original research?] Cereal grains, legumes, and milk contain bioactive substances, such as gluten and casein, that have been implicated in the development of various health problems. Consumption of gluten, a component of certain grains, such as wheat, rye, and barley, is known to have adverse health effects in individuals suffering from a range of gluten sensitivities, including celiac disease. Since the Paleolithic diet is devoid of cereal grains, it is free of gluten. The paleo diet is also casein-free. Casein, a protein found in milk and dairy products, may impair glucose tolerance in humans.
Compared to Paleolithic food groups, cereal grains and legumes contain high amounts of antinutrients, including alkylresorcinols, alpha-amylase inhibitors, protease inhibitors, lectins, and phytates, substances known to interfere with the body's absorption of many key nutrients. Molecular-mimicking proteins, which are basically made up of strings of amino acids that closely resemble those of another totally different protein, are also found in grains and legumes, as well as milk and dairy products. Advocates of the Paleolithic diet have argued that these components of agrarian diets promote vitamin and mineral deficiencies and may explain the development of the diseases of civilization as well as a number of autoimmune-related diseases.
Nutritionists agree that the Paleolithic diet is beneficial in that it cuts processed foods that have been highly modified from their raw state such as white bread, artificial cheese, certain cold cuts and packaged meats, potato chips, and sugary cereals. These often offer less nutrients than their unprocessed equivalents, and may be packed with calories, sodium and preservatives that may increase the risk of heart disease and certain cancers.
A ranking by U.S. News & World Report, involving a panel of experts, evaluated based on factors including health, weight loss, and ease of following. In 2014, it tied for last place out of 32 with the Dukan Diet.
Evidence for the effect of the switch to agriculture on general life expectancy is mixed, with some populations exhibiting an apparent decrease in life expectancy and others an apparent increase. And according to S. Jay Olshansky and Bruce Carnes, "there is neither convincing evidence nor scientific logic to support the claim that adherence to a Paleolithic diet provides a longevity benefit."
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