A Natural Diet: What is it?

In our modern world we are continually bombarded with dietary advice as to what is good and what is not good. In recent years there has been considerable emphasis on "natural foods" and "organic foods", all of which are supposedly better for you than conventional foods, whatever that is. We are told to reduce consumption of red meat, eggs, fat and salt, to eat more white meat, fish, fruits and vegetables, to drink modest amounts of red wine, and to eat lots of carbohydrates in pastas and cereals. Drinking tea or coffee may be good or bad for you depending on the latest results of some nutritional study somewhere.

All this dietary information overload provoked the questions: What is a natural diet ? How can we define a natural diet ?

First, we can look back into our evolutionary history and follow the progress of our diet over time. We, as modern humans, belong to the genus Homo sapiens which first emerged about 90,000 years ago. For about 80,000 years humans obtained food from hunting and gathering in the wild. Only in the last 10,000 years of this period has agriculture become the dominant way of providing food. A period of 10,000 years represents about 500 generations, and in this relatively short period in evolutionary time, there will only be minor genetic differences between modern man and hunter-gatherers. Consequently, if we are what we eat, then we are also what our ancestor hunter-gatherers ate. Our digestive physiology is still attuned, not to the food on the supermarket shelves, but to those items on the hunter-gatherer menu.

So what did they eat ?

Before the agricultural age, human hunter-gatherers depended on wild animals, fruits, vegetables and nuts. Curiously enough, in contrast to modern diets the hunter-gatherers consumed very little cereal grains. It seems that the diet of hunter-gatherers was 16-25% plant foods and 75-84% animal foods. Nevertheless, it would have been a very diverse diet and contained a good range of macronutrients, micronutrients and of nutricines (bioactive food components).

Life as a hunter-gather, however, was probably not too much fun and it would have been difficult to ensure that adequate supplies of food were available at all times. Also, the hunter-gatherer life style is not suited to support large settled populations. Nevertheless, a diverse diet was undoubtedly a valuable strategy in times of uncertain food supply.

Some other ideas on a natural diet may come from comparing our digestive physiology with that of other animal species on this planet that still have a natural diet. For example, true carnivores, such as the cats, have a simpler digestive system than humans, because animal products generally do not require prolonged digestion times. At the other end of the scale, plant-eaters,

such as cattle and horses, consume a large amount of cellulose which is not easy to digest but which they must use as an energy source. Vegetarian animals have evolved specially enlarged parts of the digestive tract to digest this cellulose by fermentation. This is the function of the rumen in cattle and the caecum and colon in horses. The human gut, however, does not fit neatly into either of these two extreme categories, which reflects our omnivorous or diverse food habit.

Humans also have some important nutritional requirements. For example, the omega fatty acids are important constituents of nervous tissue. Plant foods are poor in omega fatty acids, but they are quite common in animal fats and fish oils. An adequate supply of these fatty acids is particularly critical in the first five years of human life when brain growth and development is completed. Proteins of animal origin, by and large, are more easily digested by humans than are proteins of plant origin. These observations are strong evidence for an evolutionary adaptation to a meat-based diet for humans.

On the other hand, the inability of humans to synthesise vitamin C is also evidence for the necessity of foods of plant origin. Leaves and fruits of wild plants are rich in vitamin C compared to foods of animal origin and so humans have probably adapted to a diet where vitamin C is supplied from plant foods.

The development of agriculture meant that food could now be obtained in greater quantities in a more dependable fashion. However, this also brought an increased dependency upon cereal grains as a major source of food. Paradoxically, an increased dependence on cereal grains generally involves a decrease in the nutritional quality of the diet, since the major cereal grains are low or lacking in essential vitamins and minerals and have low protein quality. Consequently, people who rely on a cereal such as rice or maize as a major food source often suffer various problems of malnutrition.

The widespread and reliable availability of food now allows us Homo sapiens to choose our food items, but we still have not adapted genetically much beyond the hunter-gatherer stage. This suggests that increasing the consumption of animal products, fruits, vegetables and nuts relative to cereal grains is probably quite in line with the dietary pattern to which we humans are genetically adapted. Perhaps, a natural diet is a goodly mixture of everything from soup to nuts including plenty of meat, vegetables, fruit and wine. Fortunately, this is a diet which I find quite natural.

Dr. Adams has also written a book: NUTRICINES Food Components in Health and Nutrition. You may order your books through www.nup.com or visit his website.

Return to Article Index.

Re-print information.

Feedback or comments?