A group of scientists, from dozens of disciplines, has lately started to put together a model of the diet "designed" by evolution for the human body. When the dust settles on their investigations, most of today's arguments about human nutrition might have been laid to rest.
The new field of "evolutionary diet" is (literally) unearthing the dietary patterns of our paleolithic ancestors. The paleolithic was humanity's final formative period, stretching for hundreds of thousands of years, and culminating about 10,000 years ago.
After this time, cereal crops were domesticated, and humankind began to eat grains. This was a dramatic departure - until that moment we had evolved for at least 2 million years as hunter-gatherers and scavengers.
A scientist who has researched paleolithic diet for many years, Professor Loren Cordain of Colorado State University, says that after humans started domesticating crops, low levels of vitamins, minerals and amino acids led to "poor general health" - and a drop in human stature of 10 to 15 centimetres.
Cordain is perhaps the world authority on evolutionary diet, or "paleodiet". Paleodiet information is derived, he says, from the fossils of many human individuals, of up to 2.4 million years old.
He says that the change to an agricultural diet led to
Another paleo-scientist, Professor Arthur de Vany of California State University, puts it more pointedly: "It is easy to tell from the skeletons of our ancestors whether they were agriculturists or hunter-gatherers. The agriculturists have bad teeth, bone lesions, small and underdeveloped skeletons, and small craniums, compared to hunter-gatherers."
Naturally these findings have prompted closer study of what we were eating before the advent of agriculture - when there were lower levels of disease.
It has posed the question:
which foods has evolution equipped homo sapiens to thrive on?
Work is not complete on this, but some broad facts are emerging. First and foremost is that humans, and pre-humans, have eaten meat continuously for 2 to 3 million years. Meat has, for the most part, been the largest single component of the human diet. Our ancestors were likely more interested in animals' organs - tongue, heart, liver, kidney - than the flesh, the former having greater micronutrients and "good" fats.
Paleolithic humans' carbohydrate came chiefly from roots, tubers, leaves and wild fruits. But modern humans can't take this as license to eat large amounts of fruit. "Ancestral" fruit was vastly less sugary than today's selectively bred varieties, and far more fibrous. Replicating it from your greengrocer would necessitate concentrating on vegetables and "low glycemic index" (less sugary) fruit.
Cordain believes today's surviving hunter-gatherers provide a fair guide to the ratio of plant-to-animal food in the paleolithic diet: his surveys reveal that these people eat up to 65 per cent of their calories in animal food, and 35 per cent in plant food.
The present animal-plant ratio in the US diet is 38:62 - a near-reversal of the evolutionary pattern. Cordain cites these macronutrient ratios, in calories:
Paleolithic: fat-22% protein-37% carbohydrate-41% US today: fat-34% protein-15.5% carbohydrate-49%
So we now eat more than 50 per cent more fat than we evolved on - and much of it "new" fats, notably those in oils and dairy.
But the larger difference is in our protein consumption - which is less than half what it was.
But today's meat-eater should be careful in emulating paleolithic protein intakes, too. Ancestral game was free-ranging, and highly active. Today's slaughter animals are often fed a diet high in cereals - which does to animals what it does to humans: kicks up insulin, which tells the body to store fat. Paleo-scientists counsel eating white or lean meat.
The ancestral record does not support the SAD (standard Australian diet) - but neither does it add credence to diets seen as "natural" by vegetarians, fruitarians, natural hygienists, macrobiotic followers and their countless splinter groups.
There have been striking individual health improvements in those applying paleodiet principles - including remissions from chronic fatigue, autism, diabetes and MS. But these are one-offs. There have, as yet, been no clinical trials of the paleolithic diet - insofar as there is even consensus on what it is. And, of course, the diet of our paleolithic ancestors was inseparable from their whole lifestyle - the most crucial aspect of which was exercise.
SMH.COM.AU February 20, 2001
While I do not believe in the evolutionary perspective discussed above, I am firmly convinced that the paleolithic dietary principles are clinically valid.
In other words, they work.
We are NOT designed to eat large amounts of grains. Another principle that compounds this problem is that many people in this country are of northern European ancestry which has a particularly high predominance of gluten sensitivity.
While this frequently does not result in full blown celiac disease, it does produce pathology which leads to malabsorption and an impairment of the intestinal mucosal border which leads to the so called "leaky gut syndrome".
If you are not yet convinced of the value of low grain diets I would encourage you to review the link below which has an extensive lists of articles which explain in great detail what the central issues are.
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