Paleolithic Diet

 

The Paleolithic diet (abbreviated Paleo diet) is also known as the Caveman diet, Prehistoric diet, Stone Age diet, or Hunter-gatherer diet. It refers to the diet recently popularized by a number of authors that sets out to imitate the dietary practices of the various human species (see Homo (genus)) living during the Paleolithic period (the Old Stone Age), a period of about 2 million years duration, ending about 10,000 years ago, when Homo sapiens, invented agriculture, as well as the diet recommended by some advocates that aims to emulate the nutritional characteristics of the diets of these Paleolithic humans.

This dietary concept is concerned primarily with health issues, as opposed to ethical or economic concerns. Advocates of the Paleolithic diet believe that the best foods for the human body are those that humans are best adapted to eat, arguing that many modern ailments are diet related and can be avoided using the Paleo diet approach. Supporters of this theory argue that human genetics have scarcely changed since the Stone Age, and therefore that an ideal diet would be a reconstructed prehistoric diet such as the one humans and proto-humans used before the Neolithic Revolution. Therefore through studying archeology and modern hunter-gatherers it could be determined what a healthy diet would comprise. Interest in Paleolithic nutrition has grown in recent years as low-carbohydrate diets have become more popular, as the two practices have certain similarities.

History of the diet

One of the first suggestions that following a diet similar to that of the late Paleolithic area would improve a person's health was made in the New England Journal of Medicine in 1985.^[1] This was followed up by a book, The Paleolithic Prescription,^[2] which focused on achieving the same proportions of nutrients (fat, protein, and carbohydrates, as well as vitamins and minerals) as were present in the diet of late Paleolithic people, not on excluding foods that were not available before the development of agriculture. As such, this early version of the Paleolithic diet recommended such foods as skimmed milk, whole grain bread, brown rice, and potatoes prepared without fat, on the argument that such foods have the same nutritional properties as Paleolithic foods.

Recent versions of the Paleolithic diet, like Neanderthin : Eat Like a Caveman to Achieve a Lean, Strong, Healthy Body,^[3] focus on eliminating all foods that were not available to human beings in Paleolithic times, such as milk, dairy products, and grains. Staffan Lindeberg, a notable researcher into the paleolithic diet, has also written and spoken extensively on this dietary concept.^[4]

In the most recently published book on the Paleolithic diet, The Paleo Diet: Lose Weight and Get Healthy by Eating the Food You Were Designed to Eat,^[5] the author, Loren Cordain, synthesizes a diet from commonly available modern foods that would emulate the nutritional characteristics of the diets of Paleolithic humans.

Practices

Foods in the diet

The foods allowed in the Paleolithic diet are those that would have been generally consumed by Paleolithic humans.

In that regard, a practical, albeit imperfect, theme for adhering to the Paleolithic diet is the following : if a food item resembles one that can be found in the wild, obtained with bare hands or simple tools, and ingested immediately without cooking, processing, and by simple preparation (i.e., peeling, cracking, washing, etc.), and cause the consumer no ill effects either during or after consumption, then it can be considered edible, and therefore permissible to eat. Any food meeting this standard can then be cooked and prepared by the simplest means that are practical and consumed in modest quantities.^{[citation needed]}

The following foods are included in the Paleolithic diet:^[6][4]

• meat, preferably lean meat trimmed away of any visible fat,

• fish and seafood, preferably fresh than canned,

• fruits, preferably fresh than dried and high-in-fiber varieties,

• vegetables, including root vegetables with a low glycemic load such as beets, rutabagas, swedes, carrots, celeriac and turnips, and, in some cases, high glycemic load roots,^[7] and there is one version of the Paleolithic diet in which high glycemic load roots have been allowed for healthy individuals,^[8]

• mushrooms,

• seeds of fruit, such as flax seeds and pumpkin seeds (in moderation^[9]),

• nuts (in moderation),

• eggs (in moderation),

• honey (sparingly).

The mainstays of the diet are fresh fruits, vegetables, lean meats and seafood.^[6]

Other practitioners adhere to a less stringent version of the diet consisting of commonly available modern foods that emulate the nutritional characteristics of hunter-gatherer diets.^[10] They include one or more of the following foods in their diet:

• oils derived from those foods which can be obtained and produced through Paleolithic means and are edible in their natural, uncooked state, such as sesame oil, olive oil, and safflower oil, but not oils derived from beans (for example, peanut oil) or grains (for example, corn oil),^{[citation needed]}

• oils with healthy lipid profiles, such as canola oil, flaxseed oil and walnut oil (low omega-6/omega-3 ratio), and to a lesser extent olive oil and avocado oil (high in monounsaturated fats and low in polyunsaturates fats), but not oils such as safflower oil and corn oil, which have poor omega-6/omega-3 ratios and are mainly polyunsaturated,^[6]

• wine, for use in cooking and marinating meats, since fermented (over-ripe) fruit can be found and consumed in small quantities with little ill effect.^[6]

Foods not in the diet

Food exclusions comprise those introduced in the human food supply late in the course of human evolution, in particular after the invention of agriculture about 10,000 years ago, or those foods that are not characteristic of the retrojected diets of Paleolithic humans.

The following foods are commonly excluded from the Paleolithic diet:^[6][4]

• grains, including wheat, corn and rice,

• legumes, including peanuts, beans, peas, soybeans, tofu, soy milk and flour,

• root vegetables with a high glycemic load, such as Cassava, Manioc, Tapioca, potatoes, Taro, Parsnips, sweet potatoes and yams, except for highly fit athletes, or for healthy, normal weight individuals doing significant aerobic exercise on a daily basis,^[7] (however, not all proponents of the Paleolithic diet exclude high glycemic load roots^[8])

• refined sugars, like table sugar, corn syrup, fructose and molasses,

• processed fats and oils, such as butter, margarine, shortening, lard and peanut oil (some practitioners use certain oils as mentioned previously),

• yeast-containing foods, including baked goods, pickled foods, vinegar, fermented foods and fermented beverages,

• alcoholic beverages (some practitioners use wine as mentioned previously),

• dairy products, including milk, cheeses, yogurt and ice cream,

• fatty meats,

• salt, both refined salt and sea salt,

• soft drinks and juices,

• cashews.^{[citation needed]}

Intake

The generally prescribed proportions of protein, fat, and carbohydrate are approximately 20-35%, 30-60%, and 20-35% respectively by calories, with 35-65% of calories coming from animal foods and 35-65% from plant foods,^[11] although a version of the diet has also been advocated without any specifically prescribed ratios of animal to plant foods.^[8][12][9] Eating a wide variety of plant foods is recommended to avoid high intakes of potentially harmful bioactive substances, such as goitrogens, which are present in certain roots, vegetables, beans and seeds.^[13][9][14]

Because of the large amount of water in fruits and vegetables, the diet is, by weight, roughly 2/3 plant products and 1/3 animal products.^{[citation needed]} Consequently, because of the high water content of fruits and vegetables, it is generally accepted that slightly less non-food water is required for optimal health. This is also supported by the fact that fresh water is not always readily available in the wild and that humans must rely on other sources for their water needs. This is not a reduction in need for water, but a shift in where water can be obtained.

The vitamin and mineral content of the diet is very high compared to a standard diet, in many cases a multiple of the RDA.^{[citation needed]}

Food sources and preparation

For many practitioners of Paleolithic nutrition, the foods' source is just as important as the kind of foods being consumed. It is common practice to obtain Paleolithic foods from as natural a source as possible. Farmed meats, especially those organically farmed, are available from many natural sources, from free range poultry to grass fed beef, with many proponents preferring, though not as practical, wild game meats like quail, rabbit, and venison.

It is common practice among Paleolithic eaters that when cooking, unconventional cooking means should be avoided, such as the use of microwave ovens, and that foods are cooked just enough to kill any harmful bacteria that may be present.

As the consumption of raw foods gains popularity, some unsafe foods have occasionally entered the human diet. It is generally accepted among the supporters of Paleolithic nutrition that while it is necessary to eat only those things that can be consumed raw, it is not necessary or advisable to eat those foods raw. Many foods can harbor dangerous pathogens, including, among other things, salmonella, norovirus, and Trichinella spiralis, many of which can have serious health consequences if not first killed by means of heating, i.e., cooking. For this reason, cooking is allowed of things that, under normal healthy circumstances, would not require cooking to be consumed (grains still being discounted). The heating to an adequately high temperature of meat, poultry, and fish will normally destroy harmful bacteria and in worse cases parasite eggs (such as tapeworm). Raw eggs can also contain many harmful substances, most commonly salmonella. However, recent studies have shown that the level of salmonella infection found in commercial eggs is negligible.^[15]

Modern-day practitioners of the Paleolithic diet must be careful to get necessary nutrients found in foods that are not on the diet. For example, milk and other dairy products are a major source of calcium and vitamin D for most people following the conventional Western diet. Late Paleolithic people probably got sufficient calcium from wild vegetables and from gnawing the bones of animals they ate.^[2] Vitamin D can be synthesized by the body upon sufficient exposure to sunlight, and can be obtained from cod liver oil, and from oily fish such as salmon, mackerel, sardines, and tuna.^[16] Since cultivated vegetables have less calcium than their wild counterparts^{[citation needed]}, since excessive exposure to sunlight has been linked to skin cancer^{[citation needed]}, and since it can be expensive to eat fish several times a week, many followers of the diet may choose to take calcium and vitamin D supplements to be sure they get enough of these nutrients.

Health

The health benefits of the Paleolithic diet are, as with most dietetic theories, widely debated.

According to S. Boyd Eaton, a medical anthropologist and "evolutionary nutrition" expert from Emory University: "We are the heirs of inherited characteristics accrued over millions of years; the vast majority of our biochemistry and physiology are tuned to life conditions that existed prior to the advent of agriculture some 10,000 years ago. Genetically our bodies are virtually the same as they were at the end of the Paleolithic [variant spelling: Palaeolithic] some 20,000 years ago."^[17]

The Paleolithic diet is based on the premise that natural selection had 2 million or more years to genetically adapt the metabolism and physiology of the various human species to such a diet, and that in the 10,000 years since the invention of agriculture and its consequent major change in the human diet, natural selection has had too little time to make the optimal genetic adaptations to the new diet. According to advocates of the Paleolithic diet, physiological and metabolic maladaptations result from the suboptimal genetic adaptations to the contemporary human diet, which in turn contribute to many of the so-called diseases of civilization.^[18]

Some critics have taken issue with this logic, claiming that it is based on unilateral (genetic) adaptationistic thinking and that wrong conclusions are drawn because it does not differentiate between aptation and adaptation. In addition, they have stressed the empirical problems of reconstructing Paleolithic diets prevailing millions of years ago on the grounds that archeological data only vaguely suggest some dietary trends.^[19]

It has also been argued that just because certain foods, quantities, and preparations eaten today were not available to humans during the Paleolithic period, it does not necessarily mean that they are harmful to modern humans. In response to this criticism, proponents of the Paleolithic diet have stressed that Paleolithic foods may be essential for long-term health in the suggested proportions and quantities that modern humans would have adapted to and that when eaten, non-paleo foods necessarily replace (displace) paleo-foods and affect the diet.^[20]

In support of the theory that modern humans are best adapted to the diet of their Paleolithic ancestors, advocates of the Paleolithic diet claim that the diet of hunter-gatherer groups studied in the last century is representative of patterns for humans of 50 to 25 thousand years ago and that these modern forager groups, including the elderly, seem to be largely free of the signs and symptoms of chronic disease (such as obesity, high blood pressure, nonobstructive coronary atherosclerosis, and insulin resistance) that universally afflict the elderly in western societies (with the exception of osteoarthritis, which afflicts both populations). Moreover, when these people adopt western diets, their health declines and they begin to exhibit signs and symptoms of "diseases of civilization".^[21][22]

Furthermore, there are a number of medically diagnosed conditions whose sufferers have been shown to benefit directly from specific components of the diet. Some examples of this include:

• Coeliac disease, a gastrointestinal disorder whose sufferers are unable to digest the protein gluten, found in wheat.^[23]
• Dermatitis herpetiformis, a skin disorder linked also to digestibility issues related to gluten.^{[citation needed]}
• Gluten ataxia, a common neurological manifestation of gluten sensitivity.^{[citation needed]}
• Other conditions linked anecdotally, albeit unproven, to gluten and/or casein proteins include Multiple sclerosis, Parkinson's disease, Rheumatoid arthritis,^[24] Schizophrenia, Tourette syndrome, Chronic fatigue syndrome, Attention deficit disorder and Autism.^{[citation needed]}

Other key health benefits commonly associated with and supported by this theory include:

• Reduction or elimination of grains, dairy, and refined sugars in the human diet has shown to lower glycemic load. This is thought to lower risk of diabetes and other related syndrome X diseases by placing less stress on the pancreas to produce insulin, and preventing insulin insensitivity. A high consumption of cereal grains, even whole grains, is likely to result in a high glycemic load diet, which in turn increases the risk for Obesity, Diabetes and other diseases of the metabolic syndrome.^[25][26]

• Increasing intake of fruits and vegetables induces a net base load, as opposed to the net acidic load on the body when eating a grain based diet. This is believed to prevent osteoporosis by passing less calcium salts through the kidneys. High reliance upon cereal grains is likely to yield a positive NEAP (Net Endogenous Acid Production) that in turn could increase the risk for osteoporosis, and other diseases of acid/base imbalance.^[27][28]

• Animals that have been fed a pastural diet (free-range beef and chicken) instead of grain fed animals tend to have higher ratios of omega-3 fatty acids and other nutrients.^{[citation needed]}

• By reducing the intake of processed foods the sodium/potassium ratios in the body are more balanced.^{[citation needed]}

• Phytic acid, a chemical present in grain, is a strong chelator of important minerals such as calcium, magnesium, iron, and zinc. It, in essence, 'binds up' these minerals, and since humans lack the digestive enzyme phytase required to break this bond, these important minerals are not bioavailable, contributing significantly to mineral deficiencies. This problem is increased when dietary mineral supplements are not available, such as in developing countries.^{[citation needed]}

• Lectins present in cereal grains and legumes have the potential to cause auto-immune diseases, like rheumathoid arthritis, by a process called molecular mimicry (similarity of structure shared by products of dissimilar genes).^[29][30][31]

• Dairy products, especially those derived from cow's milk, are more or less correlated with a variety of health issues, including type 1 diabetes,^[32] prostate cancer,^[33] multiple sclerosis,^[34] and Crohn’s disease.^[35] They also don't always make life any easier for Type 2 diabetics: milk, yoghurt, and cottage cheese have low glycemic indices but are highly insulinotrophic, with an insulin index similar to that of white bread.^[36][37]

Archeological and Anthropological Evidence

Milk and dairy products were not consumed prior to the agricultural revolution, i.e. prior to the domestication of milk-producing animals.^[20] Mature lactose tolerance is perhaps the most recent evolutionary change in humans, a phenomenon unique to humanity; it evolved independently in several regions (as noted above), but is not a universal trait in modern man -- although fermented dairy goods tend to be more readily digestible than unfermented.^{[citation needed]} Dairy products have been very valuable historically (in post-Agricultural-Revolution times) as a cheap and reliable source of protein, particularly in Europe, the Middle East, and India.^{[citation needed]}

It has been established that wild tubers would have been a common component in historically studied hunter-gatherer diets, comprising 23.6 % of all the plant food consumed by the average hunter-gatherer.^[11] High glycemic load tubers (such as potatoes, which were developed from intensive agricultural inbreeding of wild types), however, would not have been part of pre-agricultural diets.^[38] Most tubers, and many underground plant structures (corms, roots, etc) are inedible unless cooked. Cooking serves to breakdown the cell walls and make the starch available for absorption and it also inactivates potentially toxic compounds. Hence, until hominins could regularly control fire (~300,000 years ago), most roots were inedible.^[10]

Historical and ethnographic studies of hunter gatherers indicate that cereal grains were rarely consumed.^[39] However, there are some notable exceptions: Holocene hunter gatherers living in marginal areas such as desert ate grains seasonally such as the Great Basin Indians in the U.S. and Australian Aborigines. More importantly, for most of humanity’s existence on the planet, up until the very end of the Paleolithic period grains were never consumed. Grains are virtually indigestible unless the cell walls are broken via (grinding or milling) and the starch is gelatinized by cooking. Hence the appearance of stone grinding tools (mortar and pestle, saddle stones etc) heralds the widespread use of grains in hunter-gatherer societies. The first documented record of stone grinding tools appearing in the fossil record occur 22,500 – 23,500 years ago in the near East,^[40][41] and the first hunter gatherer society known to have made wide scale use of grains were the Natufians who lived in the Levant ~13,000 years ago. Hence, cereal grains have little or no evolutionary precedent in hominin diet.^[10]

There is evidence that legumes were not generally consumed before the agricultural revolution.^[42] However, recent archeological finds indicate that large seeded legumes were part of the human diet long before the neolithic agricultural revolution.^[43][44]

Sustainability

Environmental sustainability

It has been estimated that, worldwide, agricultural activity, especially livestock production accounts for about a fifth of total greenhouse-gas emissions. Accordingly, the reduction of the average worldwide consumption level of animal products to 90g per day has been proposed as a means to fight global warming.^[45] In addition to its role in climate change, the current production of livestock has been claimed to increase land degradation, air pollution, water depletion and pollution, and loss of biodiversity.^[46] Whether the Paleolithic diet can currently be environmentally sustainable depends on the ratio of plant to animal foods consumed. In that regard, it is worthy to note that a version of the Paleolithic diet without any specifically prescribed ratios of animal to plant foods has been advocated.^[8][12][9] Furthermore, policies have been proposed to address livestock's impact on the environment^[46] and alternatives to large-scale industry agriculture have been suggested for sustainable animal and plant-food production.^[47] There are also concerns that a widely adopted Paleolithic diet including fish would destroy the world's fisheries. However, informed consumers can buy fish produce that comes from well managed fisheries and has not contributed to the environmental problem of overfishing.^[48]

Economic sustainability

If the Paleolithic diet was widely adopted, there are concerns that not enough food could be produced to feed the world population^[10] and that, when produced, this food would be unaffordable. Providing fresh food free of preservatives on a large scale could introduce logistical challenges that would increase costs to producers and retailers. The advantages gained by using foods that are designed for longevity (e.g. cereal grains, legumes, salted foods) in storage would be lost. These additional costs could make food less affordable. That being said, the economic cost of sustaining the world-wide consumption of a Paleolithic diet must be evaluated in light of the possible savings resulting from the health-promoting benefits that such a diet may have. Moreover, the gathering of wild food plants appears to be an efficient method of subsistence that could prove instrumental in preventing malnutrition if the Paleolithic diet was widely adopted.^[49]

Paleolithic diet for animals

Pet food diets such as the BARF Diet (Bones and Raw food) (Biologically Appropriate Raw Food) for dogs and Prey Model Diet for cats are directly analogous to the Paleolithic diet for humans. Proponents of raw feeding note that cats and dogs are carnivores that have evolved to survive on raw meats, bones, offal, and small amounts of leafy plants, and are concerned that modern commercial pet foods contain a high proportion of health compromising grains, salt and sugars.^[50]

See also

Related info

• Medical research related to low-carbohydrate diets
• Neolithic Revolution
• Natural selection
• List of diets

Other related diets

• Atkins Diet
• Low-carbohydrate diet
• Gluten-free diet
• Gluten-free, casein-free diet
• Blood type diet
• Candida control diet
• Joel Fuhrman diet
• The G.A.R.D. Diet The Glutamate-Aspartate Restricted Diet is very similar to the Paleolithic diet
• Gerson diet
• Hunza diet
• Raw food diet
• Organic food diet
• Natural Foods Diet
• No-Grain Diet
• Specific Carbohydrate Diet
• Bushmeat
• Zone diet has similar protein:fat:carbohydrate ratios
• The Optimal Diet
• Zero-Carb Diet

Bibliography

Footnotes

External links