The nature of the evidence
We at NutritionalAdvisor.com believe that in a biochemical sense we are not simply what we eat, as it is frequently propounded in the media, but equally what our ancestors ate. It is their foods and eating habits that have largely shaped our genetic code. One of our aims is to closely examine what exactly did our ancestors eat, and if possible how they nourished themselves and their offspring.
In historical times, written records let us glimpse at the foods and eating habits of our ancestors. Numerous texts, especially by the comedy writers of antiquity, tell us not only what our ancestors ate, but also the preparations they used. As we move backwards into prehistoric times, we depend more on archeological excavations for our data, which become progressively more incomplete the further back we go. By the time we reach our rain forest period, our ignorance is rather embarrassing, as you saw under The Heritage Factor. But the subject of our early nutrition is vital for us and must be pursued a little further.
Archeological excavations may uncover some primitive stone tools, which let us speculate about their uses. Or we may recover the bones of some large fauna, and from the way they are broken or scratched we may reflect on whether they show human intervention. We sometimes recover human, hominid or hominoid bones, but these tell us relatively little about their foods, and only about their overall diet. Their dentition may sometimes be informative, but not often. Field and laboratory studies have shown that the microwear patterns we study on the surface of teeth change rapidly, and the information they provide concerns mainly what foods were eaten just prior to death. That is not a safe guide to their overall nutrition.
An important question
This kind of scattered bits of speculation is hardly enough to help us understand the diet of our distant ancestors. We know virtually nothing about the plant foods they ate, except that they changed often between the C3 (forest vegetation) and C4 (savanna vegetation) pathways, information obtained from bone isotopic evidence. This lack of direct evidence is partly due to the pH (acidity measure) of rain forest waters, which is unusually acidic. Under such conditions no organic materials can survive two dozen years, never mind several million.
Partly, it is because the forest floor is strewn with plants that do not grow through the well-known process of photosynthesis and the use of chlorophyll, but by assimilating organic materials directly from the forest floor. These plants are called Thallophyta (algae, fungi, lichen, etc), and many are small enough to be nearly invisible. Thus acid ground conditions and thallophyta clean the forest of organic residues. For these reasons, excavations in the rain forest for the purpose of learning what our distant ancestors ate, are exercises in frustration and futility.
On the other hand, saying that our ancestors ate exactly the same foods as the other higher primates still eat, is not really saying much. This is only a gross assumption, and besides, all higher primates don't have the same diet. This assumption also fails to explain an extremely important difference already mentioned in an earlier section (see THE HERITAGE FACTOR). Namely, that our ancestors left the rain forest, while all other higher primates still live in rain forest habitats. Why? The question is hardly academic. As you will see immediately below, what keeps the other primates in the rain forest is their food supply. If we earlier ate the same foods as they, why didn't that keep our ancestors there too?
The question is particularly relevant. Most animals and all plants manufacture vitamin C from glucose. But we humans, the rest of the primates, and a couple of other species like hamsters and some fruit-eating bats, are the only animals that cannot manufacture vitamin C in our bodies, and must obtain it from our foods. The rain forest is obviously the best place to be for beings with our needs, and without tools, utensils, or weapons. But then why did we leave?
Puzzles of the Hippocratic Code
This and many similar questions, which we try to answer as best we can, often provide enlightening insights into human nutrition and its effects on our health. But our interests necessarily extend to much more recent ancestors, and hence our research covers many traditional diets and the traditional Mediterranean diet in particular. Here we have much more information in the ancient Greek texts, but which is sometimes and initially no less puzzling for that. So for example, in a Hippocratic text of the 5th century BC and one of the few that may possibly be attributed to Hippocrates himself, we read in connection with legumes or pulses:
And do not eat these, except together with cereal products 
Two score of years ago, nutritionists and other knowledgeable people would have smiled condescendingly at the injunction. Legumes and cereals are very similar foods and consist essentially of a mixture of carbohydrates and proteins, with legumes containing more proteins than cereals. What sense does it make eating such similar foods together? Today, we know better. Both classes of proteins are incomplete, that is, they do not have all the amino acids necessary for manufacturing all the proteins we need, such as the multitude of hormones, enzymes, neurotransmitters, and so on. But taken together, they form complete proteins. Only this is recent knowledge and presupposes an understanding of nutrition that the ancient Greeks could not possibly have. Then how explain this clear-cut admonition by the greatest physician and nutritionist of antiquity?
Agents against chronic degenerative disease
This is another kind of question we try to answer. And together with this sort of puzzler, vital questions such as how is it that virtually all the foods included under the rubric of Traditional Greek Mediterranean Diet, such as olive oil, fruits and vegetables, pulses, breads and other cereal products, wild greens, bulb vegetables, almonds and walnuts, figs, chestnuts, roasted chick peas, pumpkin seeds, fat fish, yogurt, wine, and so on, are all well-known agents against chronic degenerative diseases, like obesity, heart disease, strokes, cancer, hypertension, arteriosclerosis, etc.
We try to use this knowledge so as to prevent, and when necessary help to overcome, the major killers of the 20th century that have grown out of all proportion in the new millennium, and to an extent, to help us stop vacillating from Stoneagers on the brink to Stoneagers on a junket.
- Hippocratic Code. Περί Διαίτης οξέων (Regimen in Acute Diseases) 18.