Paleolithic Diet

The paleolithic diet (abbreviated paleo diet or paleodiet), 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. In common usage, such terms as the "Paleolithic diet" also refer to the actual ancestral human diet.

Centered on commonly available modern foods, the "contemporary" Paleolithic diet consists mainly of fish, grass-fed pasture raised meats, vegetables, fruit, fungi, roots, and nuts, and excludes grains, legumes, dairy products, refined salt, refined sugar, and processed oils. There are many different alternatives that are available to replace the foods that have been eliminated. For example, coconut oil can be substituted for butter, almond flour can be substituted for white flour, and honey can be substituted for other sweeteners.

First popularized in the mid-1970s by gastroenterologist Walter L. Voegtlin, this nutritional concept has been promoted and adapted by a number of authors and researchers in several books and academic journals. A common theme in evolutionary medicine, Paleolithic nutrition is based on the premise that modern humans are genetically adapted to the diet of their Paleolithic ancestors and that human genetics have scarcely changed since the dawn of agriculture, and therefore that an ideal diet for human health and well-being is one that resembles this ancestral diet. Proponents of this diet argue that modern human populations subsisting on traditional diets allegedly similar to those of Paleolithic hunter-gatherers are largely free of diseases of affluence, and that two small prospective studies of the Paleolithic diet in humans have shown some positive health outcomes. Supporters point to several potentially therapeutic nutritional characteristics of allegedly preagricultural diets.

This dietary approach is a controversial topic amongst dietitians and anthropologists, and an article on the National Health Service of the United Kingdom Choices website suggests that it may be a fad diet. Critics have argued that if hunter-gatherer societies failed to suffer from "diseases of civilization", this was mostly due to reduced calories in their diet, shorter average lifespans, or a variety of other factors, rather than some special diet composition. Some researchers have taken issue with the accuracy of the diet's underlying evolutionary logic.

Also disputed are some dietary recommendations and restrictions on the grounds that they provide no health benefits or pose health risks and are not likely to accurately reflect the features of ancient Paleolithic diets.

A 2011 ranking by U.S. News & World Report, involving a panel of 22 experts, ranked the Paleo diet lowest of the 20 diets evaluated based on factors including health, weight-loss and ease of following. These results were repeated in the 2012 survey, in which the diet tied with the Dukan diet for the lowest ranking out of 25 diets; U.S. News & World Report stated that their experts "took issue with the diet on every measure". However, one expert involved in the ranking stated that a "true Paleo diet might be a great option: very lean, pure meats, lots of wild plants. The modern approximations… are far from it." He quickly added that "duplicating such a regimen in modern times would be difficult."

The ranking assumed a modernized offshoot to the paleo diet in which low-carb is emphasized, this diet specifically containing only 23% carbohydrates. Higher carbohydrate versions of the paleo diet, which allow for significant consumption of root vegetables, were not a part of this ranking. Loren Cordain, a proponent of a low-carbohydrate Paleolithic diet, responded to the U.S. News ranking, stating that their "conclusions are erroneous and misleading" and pointing out that "five studies, four since 2007, have experimentally tested contemporary versions of ancestral human diets and have found them to be superior to Mediterranean diets, diabetic diets and typical western diets in regards to weight loss, cardiovascular disease risk factors and risk factors for type 2 diabetes." The editors of U.S. News replied that their ranking included a review of all five studies which found that all of them were small and/or of short duration.