A ccording to the modern reconstructions by anthropologists, the Neolithic revolution began in the Middle East at about 10,000 bce. It is defined as marking the change from hunter-gatherer groups to agricultural societies and brought about a drastic change in the nature of human diets, but, it is claimed, not in our genes. The shift to agriculture was a gradual one; however, by 7,500 bce, most people in the Middle East had switched to an agrarian way of life, and the first state was born by 5,500 bce. The Industrial Revolution in eighteenth-century Europe brought about another major shift in human diets without any alteration in our underlying genetic makeup.
The Paleolithic Diet is based on the premise that these shifts in diet without shifts in genetics or anatomy that have caused the "diseases of civilization" such as high blood pressure, Type 2 diabetes, obesity, and even cancer (Eaton et al. 1988a). The promoters of the Paleolithic Diet base these claims on evidence gathered on the few remaining hunter-gatherer groups who have almost no occurrence of these diseases (Eaton et al. 1988a). This is in direct contrast to developed and developing nations where these diseases are becoming more and more rampant (Dehghan et al. 2005; King et al. 1998). Thus, the "Paleolithic Prescription" claims that if we shift back to our ancestral diet, we can once again be healthy.
The claims of the Paleolithic Diet are simple; with a return to a preagricultural diet and an increase in exercise, the "diseases of civilization" would decrease, people would live longer and healthier lives, and there would be no more obesity in the world. This, however, is the claim of almost all diets. Nevertheless, this diet is special for two reasons: It is scientifically supported, and many popular diets today, such as Atkins, have used this science as a justification for their diets. While, thus far, the diet appears sound, there are important factors to consider.
The diet's claims rest on correcting two misconceptions concerning life expectancy and stature. The average life expectancy for Paleolithic humans was much lower than that of Americans today, though this was mostly due to the very high infant-mortality rate. If a child actually lived through childhood, its life expectancy was actually much higher than the average. There has even been evidence from some Neanderthal fossils of a social network that helped the elderly survive. Stature is an important indicator of dietary quality because without proper nutrition in one's childhood and adolescence, growth will be stunted. Interestingly, most of our Paleolithic ancestors were not radically shorter than the average for modern Americans about 177.8 cm (70 inches) for males and 147.8 cm (58.1 inches) for females. Fossil evidence has even shown that some individuals were as tall as 188 cm (74 inches) (Eaton et al. 1988a). This means that the nutritional quality of the diet in Paleolithic times was very close to what it is now and that people had enough to eat. It is also important to ask how we know what foods our Paleolithic ancestors were eating.
The ideal diet of Paleolithic humans was extrapolated from data collected from living hunter-gatherer groups. This data shows that most (73 percent) of these groups ate far more meat than the average American does with more than 50 percent of their energy coming from meat. This, combined with the lower carbohydrate content of wild plants, means that these groups derive about 19-35 percent of their energy from protein and about 22-40 percent from carbohydrates (Cordain et al. 2000). Also, most of these groups consume little to no dairy products
(Eaton 2006). Although modern hunter-gatherer groups rely heavily on meat, like the Paleolithic hunters and gatherers most likely did, they strike a balance between protein, fats, and carbohydrates. As Cordain explains this balance must occur because human beings cannot process food which is excessively high in protein (Cordain et al. 2000: 682). This is especially important to note because of the popularity of low-carbohydrate diets, such as Atkins and South Beach. It is also important to look at the food pyramid put out by the United States Department of Agriculture, which is very different from our ancestral diet.
The Paleolithic Prescription also blames the heavy increase of sodium, refined sugars, and drugs, most especially alcohol and tobacco, for the rise in obesity in the modern world. Humans today are the only mammals that actually consume more sodium than potassium. The increased availability of sodium today is one of the reasons for this, but the decrease in potassium-rich foods in the modern diet is also partly responsible. In Paleolithic times, the only source of refined sugar was honey, and this accounted for only about 2 percent of the caloric intake of Paleolithic humans. This is in stark contrast to the 15 percent that refined sugars now add to our caloric intake. Alcohol, though not necessarily completely lacking from Paleolithic times as "some fruits and grains do naturally ferment" (Eaton et al. 1988b: 23), would have been scarce; it now makes up a significant part of the diet of the average American at 7-10 percent of the daily caloric intake. This is even more amazing when it is factored in that many Americans do not drink. Tobacco, although not usually consumed to provide caloric intake, does affect a person's metabolic rate and thus can contribute to obesity.
The authors of The Paleolithic Prescription do not advise a return to the Paleolithic way of life but instead recommend picking and choosing the healthier aspects of the Paleolithic way of life. To give up the advances of modern medicine and the battles that humans have won against microbes would be foolish, but the authors claim that these victories have come with a price: our overall fitness. The human body, which has not substantially changed in about 35,000 years, was designed to be energy efficient when walking long distances in order to acquire food, but humans in developed nations today rarely do more than walk around the supermarket to acquire their food. Evidence shows that Paleolithic humans would routinely travel about 5 miles in their search for food. Walking
5 miles is double the USDA's current recommendation for daily physical activity (the USDA Food Pyramid). However, it is also true that Paleolithic people most likely only did this about three to four times per week. Exercise is a key foundation of this diet and one that many other diets today tend to overlook.
This diet is based on science; however, the science is highly speculative. The world that modern hunter-gatherers live in is much different from the world our Paleolithic ancestors lived in. Thus, it is hard to determine exactly what resources would have been available to our ancestors; so much of this evidence must be questioned. No clear first-hand evidence exists for what Paleolithic people actually looked like; what we do have is based on cave paintings and forensic reconstructions. Moreover, forensic reconstructions are one of the most controversial parts of anthropology because of their subjective nature. Though life expectancy was much longer if one matured to adulthood, the quality of adult life in the Paleolithic is questionable. The same Neanderthal fossil used to show social care for the elderly also has clear evidence of arthritis.
Much of what is said about the Paleolithic diet is based solidly in good science, but there are parts of it that are nothing more than speculation. There is the underlying assumption that our problems with obesity stem from our diets not our genes. Humans are hyper-omnivorous, meaning we can eat just about anything, but the authors of The Paleolithic Prescription seem to ignore this evolutionary fact and concentrate on the information gathered from a few ethnographic studies of a very small number of modern people. This data does nothing to answer the question of why did humans develop as hyper-omnivores and maintain this trait into modern times.
SLG/Joe Bauer See also Atkins; Food Pyramid; Natural Man; Smoking
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When over eighty years of age, the poet Bryant said that he had added more than ten years to his life by taking a simple exercise while dressing in the morning. Those who knew Bryant and the facts of his life never doubted the truth of this statement.