By Beatrice Trum Hunter
Published in Consumers' Research Magazine, July 1985
Reprinted With Permission By Author
What is an optimal diet for humans? This intriguing question is raised repeatedly, and a definitive answer remains elusive. Two recent reports from medical journals are of general interest and also deal with the question. Both describe pre-industrial diets. While we cannot return to the lifestyle of our ancestors, study of their dietary habits might contribute some insights into our own best bets where diet is concerned.
In one recent experiment, 10 Australian aborigines with diabetes agreed to return to their hunter-gatherer lifestyle. Previously, while in an urban setting on the outskirts of Melbourne, the aborigines had maintained Western lifestyles, partaking of meals that consisted, in part, of fatty meats, carbonated soft drinks and alcohol. They had become obese and had developed high blood pressure and diabetes.
Returning to the wild, they consumed only what they could obtain by hunting and fishing kangaroo,turtle, and crocodile, for example. With much activity expended in the search for food and consuming only about 1,200 calories daily, they lost their excess weight within several weeks. After two months in the wild, their blood sugar levels fell. There was significant improvement in their bodies' ability to remove sugar from the blood after eating, and they experienced a partial, and in some cases complete, reversal of adult-onset diabetic abnormalities.
These findings confirm results of other studies showing that, in cases of adult-onset diabetes, normal functioning of the insulin-secreting cells in the pancreas can be partially restored if high blood sugar levels are reduced. According to the researcher conducting the aborigine study, the main finding was that "a low-fat, low-calorie is an effective diet for control of diabetes....The low-fat content of the diet may be one of the most important therapeutic components, particularly for reducing the vascular complications of diabetes." This conclusion is remarkably similar to many of the present-day dietary recommendations for achieving and maintaining general health.
Elsewhere, the dietary habits of paleolithic humans have come under renewed investigation. Researchers have noted that humans today "are confronted with diet-related health problems that were previously of minor importance and for which prior genetic adaption has poorly prepared us. Chronic illness affecting older, postreproductive people could have little selective influence during evolution, yet such conditions are now the paramount cause of morbidity in Western nations." The food of "stone age" humans is regarded as having "the nutrition for which human beings are in essence genetically programmed."
Differences between the diet of our remote ancestors and that of present industrialized society have important implications for health. Increasingly, physicians and nutritionists are convinced that the dietary habits adopted by Western civilization over the past century contribute to coronary heart disease, high blood pressure, diabetes and some types of cancer. These conditions, which have become dominant health problems only recently, are virtually unknown among the few surviving hunter-gatherer populations whose food habits resemble the stone-age diet. How did some of these differences come to be?
The introduction of agriculture, a mere 10,000 years ago, radically changed human nutritional patterns. The proportion of meat in the diet declined drastically, while vegetable food came to comprise up to 90% of the total diet. As a result, people came to be considerably shorter than they had been in pre-agricultural times. Their skeletal remains show sub-optimal nutrition, both from protein-calorie deficiency and the interactions between malnutrition and infection. Since the Industrial Revolution, the animal-protein content of Western diets has become more nearly adequate. Once again, we are nearly as tall as the early, biologically modern humans. However, our diets still differ markedly from theirs, and these differences are crucial in what has been termed "affluent malnutrition."
For example, the animal protein eaten by paleolithic populations (deer,bison,horse, mammoth, etc.) differed considerably from the meat available to us in the modern supermarket. It had less total fat, more essential fatty acids ( emphasis mine) and a much higher ratio of polyunsaturated to saturated fats than ours does. The fat of wild animals contains an appreciable amount of one particular fatty acid, now being investigated for its possible property of preventing the development of atherosclerosis.(emphasis mine). Domestic beef contains nearly undetectable amounts of this valuable nutrient. Meat from free living animals contains fewer calories and more protein per unit of weight than meat from domesticated animals. Our paleolithic ancestors consumed more structural fat and less depot fat.
Foods from the vegetable kingdom reflect another difference between our ancestor's diet and ours. As foragers they ate a wide range of roots, beans, nuts, tubers, fruits and, at times, even flowers and edible gums. We have a relatively narrow variety of domesticated crops produced by horticulturists and traditional agriculturists. Furthermore, many of our domesticated plant foods have higher ratios of starch to protein than do their wild counterparts.
The paleolithic diet not only differed substantially from the typical Western diet of today, but it also differed somewhat from the recommendations currently advocated by nutritionists and federal agencies. The foods we eat are classified into four basic groups: protein foods, fruits and vegetables, dairy products and grain products. We are encouraged to have two or more daily servings from each group to achieve balance. But our ancestors who lived prior to the development of a stable agriculture of domesticated crops and animals, derived all their nutrients solely from the first two food groups. Dairy foods were non-existent, and cereal grains were rare. Yet various estimates, using modern standards, reveal that the paleolithic diet offered the health benefits of much more fiber than is now contained in a typical western diet, and the sodium intake of our remote ancestors was only one-sixth
of that present in the typical salt-laden American diet.
Of what value are these findings? The extent to which some major chronic diseases of industrialized society are related to the typical Western diet is now being critically analyzed. Evidence of linkage is accumulating steadily. Medical research in diverse fields are beginning to formulate a generally preventative diet against such conditions as atherosclerosis and cancer. The diet of our remote ancestors cannot be duplicated by us, but it can serve as a reference standard for modern nutrition as we continue to strive toward that elusive goal: achieving an optimal diet.
The author, Beatrice Trum Hunter, MA, has written more than 30 books on food and environmental issues, frequently before widespread public awareness. She was food editor of Consumer's Research Magazine for more than two decades. She is an honorary member of The Price Pottenger Nutrition Foundation, as well as an honorary fellow of The International Academy of Preventative Medicine and an honorary member of The American Academy of Environmental Medicine. She has been the recipient of many awards, including The Jonathan Forman Award of The Society for Clinical Ecology, The New Hampshire Society for Preventative Dentistry, and The Donnon Pepper Humanitarian Award. She can be reached at 243 Falls Road, Deering, N.H. 03244