Most of us have healthy intentions when it comes to the food we eat. But it can be tough. Especially when you consider that our bodies haven't properly adapted to our highly processed fast food diets.

by Cindy Engel

The only way to keep your health is to eat what you don't want, drink what you don't like, and do what you'd rather not.
- Mark Twain, 1897

In the United Kingdom, suicides by young men have increased by 176 percent since 1985, and according to the World Health Organization, depression currently disables 20 percent of the global population. Economic and technical progress is no assurance of good health.

Humans are qualitatively different from other animals because we manipulate the flow of energy and resources through the ecosystem to our advantage, and consequently to the detriment of other organisms. That is why we compete so successfully with other species. But with this success come some inherent failings, particularly in terms of our health.

Image Credit Influenza virus (an Orthomyxovirus) is responsible for acute upper respiratory disease, usually accompanied by fever and myalgia.

According to physician Boyd Eaton and his anthropologist colleagues, despite all our technological wizardry and intellectual advances, modern humans are seriously malnourished. The human body evolved to eat a very different diet from that which most of us consume today. Before the advent of agriculture, about ten thousand years ago, people were hunter-gatherers, living on fruit, vegetables, and lean meat. The foods varying with the seasons and climate, and all obtained from local sources. Our ancestors rarely, if ever, ate grains or drank the milk of other animals. Although ten thousand years seems a long time ago, 99.99 percent of our genetic material was already formed. Thus we are not well adapted to an agriculturally based diet of cereals and dairy products.

Our genes evolved to work in an environment of a hunter-gathering diet. Although adaptation has continued, at least one hundred thousand generations of people were hunter-gatherers; only five hundred generations have depended on agriculture, only ten generations have lived since the onset of the industrial age, and only two generations have grown up with highly processed fast foods. There has simply not been time for our bodies to adapt to such a dramatic change. Physicians Randolph Nesse and George Williams write: "Our bodies were designed over the course of millions of years for lives spent in small groups hunting and gathering on the plains of Africa. Natural selection has not had time to revise our bodies for coping with fatty diets, automobiles, drugs, artificial lights, and central heating. From this mismatch between our design and our environment arises much, perhaps most, preventable modern disease."

Do we really want to eat like prehistoric humans? Surely "cavemen" were not healthy. Surely life was hard and short. Apparently not. Archaeological evidence indicates that these hunter-gatherer ancestors were robust, strong, and lean, with no sign of osteoporosis or arthritis-even at older ages.

DNA Molecule

Paleolithic humans ate a diet similar to that of wild chimpanzees and gorillas: fresh raw fruit, nuts, seeds, vegetation, fresh untreated water, insects, and wild-game meat low in saturated fats. Much of their food was hard and bitter. Most important, like chimpanzees and gorillas, prehistoric humans ate a wide variety of plants-an es- timated one hundred to three hundred different types in one year. Nowadays, even health-conscious Westerners seldom consume more than twenty to thirty different species of plants. A broad range of plants provides not only essential vitamins and minerals but also valuable secondary plant compounds integral to preventive and curative medicine.

The early human diet is estimated to have included more than 100 grams of fiber a day. Today the recommended level of 30 grams is rarely achieved by most of us. Humans and lowland gorillas share similar digestive tracts-in particular, the colon-but while gorillas derive up to 60 percent of their total energy from fiber fermentation in the colon, modern humans get only about 4 percent. When gorillas are brought into captivity and fed on lower-fiber diets containing meat and eggs, they suffer from many common human disorders: cardiovascular disease, ulcerative colitis, and high cholesterol levels. Their natural diet, rich in antioxidants and fiber, apparently prevents these diseases in the wild, suggesting that such a diet may have serious implications for our own health.

NASA Photo by Tony Landis Monkeys on a film set

Contemporary hunter-gatherer societies still eat in the traditional way and, like our prehistoric ancestors, have far less cancer, heart disease, diabetes, and osteoporosis than those of us who forage in supermarkets. "Sickness is much more prevalent, pervasive, and diverse among agriculturists than among hunter-gatherers," explains anthropologist Michael Logan, and it is not because the hunter gatherers die before these ills can develop. A decline in health is seen with the transition to agriculture. As native tribes of what is now the south central United States abandoned their hunter-gathering lifestyle some fifteen hundred years ago, their worsening health was indelibly recorded in their skeletal remains. Although more of them survived the famines than did their ancestors, they were not as healthy. They were less robust and showed signs of deficiencies of vitamin B, iron, and protein. Agriculture overcomes the vagaries of seasonal food supply, but at a price. And as contemporary hunter gatherers change to an industrialized diet high in fats and sugar and low in fiber, they too develop the diseases of the industrial world.

Agriculturists select and domesticate plants for ease of cultivation and palatability. Over time they have chosen plants with fewer bitter-tasting or astringent secondary compounds, and these plants are inevitably more susceptible to disease. Modern crops, therefore, need more chemical intervention than wild plants, which retain their own defensive pesticides. Consuming modern crops is consequently very different from consuming wild plants, and when we eat the meat of domesticated animals fed on these domesticated plants, our total intake of beneficial plant compounds is far lower than if we had eaten wild game.

NOAA Native tribe in the southern Philippines - Hundreds of tribes and over a 100 dialects were found in the Philippines during the 1930's

Furthermore, agricultural biodiversity is shrinking as fewer species and varieties are made available for cultivation. Today 75 percent of the global food supply comes from a mere twelve crop species. Not only are we losing species diversity but we are losing varieties within those species. The demise of dietary diversity is exacerbated by modern processing, in which artificial chemicals instead of herbs are used to preserve, enhance the taste of, and add colour or other properties to food. Our industrial diet is greatly weakened thereby in both nutritional and medicinal attributes, providing us with only the bare essentials of energy and protein.

Not all agricultural societies have taken the same road. Many traditional agriculturists maintain the diversity of their diet by eating a variety of herbs and other plant compounds along with meat and grains. The Huasa people of northern Nigeria, for example, traditionally include up to twenty wild medicinal plants in their grain based soups, and peoples who have become heavily reliant on animal products have found ways of countering the negative effects of such a diet.When animal fat is metabolised in the body, it produces damaging free radicals that contribute to cardiovascular disease, cancer, and aging.

Masai Warrior

While the Masai of Africa eat meat and drink blood, milk, and animal fat as their only sources of protein (animal fat makes up 60 percent of their energy intake), they suffer less heart trouble than Westerners. One reason is that they always combine their animal products with strong bitter, antioxidant herbs-up to twenty-eight additives in each meat-based soup, and twelve substances added to milk! In other words, the Masai have balanced the intake of oxidizing and antioxidizing compounds. According to Timothy Johns, it is not the high intake of animal fat, or the low intake of antioxidants, that causes so many health problems in industrial countries; it is the lack of balance between the two.

Eating the right foods and natural medicines requires a sensitivity to subtle changes in appetite. Do I fancy something sweet, sour, salty, stimulating, or sedating? What sort of hunger is it? And, after consumption, has the "need" been satisfied? Such subtleties are easily overridden by artificially created superstimuli in processed foods that leave us unable to select a healthy diet. We need to listen more carefully to our body's cravings and take an intentional role in maintaining our health before disease sets in.

An abridged extract from Wild Health - How Animals Keep Themselves Well and What We Can Learn From Them by Cindy Engel (c) Used with permission. Published by Weidenfeld and Nicolson in the UK and Houghton Mifflin Company in the US Available to buy from Amazon.co.uk and Amazon.com Cindy Engel earned a PhD in animal behaviour from the University of East Anglia. As well as lecturing for the Open University, she is also a freelance radio and television science advisor.