We received the following question by e-mail in June 2009:
I was reading evfit.com for training/diet related tips and it got me thinking:
Whilst the palaeo diet (the word "diet" gives me images of overweight westerners, I am using it for want of a better term) makes absolute sense, I began thinking that these diets are bioregion specific diets i.e the contents of the diets would have varied substantially across different ecological circumstances and across seasons. Almost all of these diets would contain the same food types more or less: fresh meat, fruit and vegetables, herbs nuts etc, although the specific contents of the diets would vary significantly. A Pleistocene "european's" meat would have been deer/sheep whilst Pleistocene Aborigine's would have been kangaroo etc.
To cut a long story short, do you think that all Palaeo diets are essentially appropriate or does our european genetics and digestive system favor a palaeo diet based on the specific foods that our ancestors would have eaten?
Of course in a 'future primitive' world, our food would once again be provided by our ecological surrounds, a long way from the northern hemisphere! environment.
Good thoughts. There is no definitive answer. In my own mind I look most closely at our ancestors going back as far as Homo habilis ("handy man" - they were the earliest of the toolmakers - so much so that they are classified by the type and sophistication of the tools they made and used), a species that arose in the Pleistocene and continued through the first third of the Palaeolithic. Their use of tools enabled them to eat meat and also to hunt rather than scavenge. With more meat, their brains grew and they became smarter. I don't look closely back further into the Australopithecines (they were scavengers [lacking hunting weapons and skills], ate termites, tubers, grass roots, the remains of prey from carnivore species - real opportunistic omnivores]. But my interest sharpens as habilis evolves into H. ergaster. Ergaster evolved in Africa (they were the first species that lived as hunter-gatherers), giving rise to H. heidelbergensis and these evolved into Neanderthals. As this line died out (or were exterminated, like the megafauna, by H sapiens - it's what our species does), their lifeway is of no direct interest to us from a palaeo living perspective. H ergaster also had a second major line of descendants that leads to us. They came "out of Africa" (what a wonderful phrase!) and those that did so are referred to as H. erectus as the species fans out from the Red Sea area from about 1.8m years ago. These are the people I am most interested in. They were, on average, taller than we are - they used their big brain to live well - coming closer to maximizing their genetic potential more than we do today. H. habilis males were only 130 cm tall; erectus averaged 180 cm.
Now, to answer your question, their food intake would have varied by day, by season and according to where they lived. This means the food would have varied in quantity as well (particularly in respect of the plants). Coastal people would have almost lived on shellfish as these would be virtually abundant pre-packaged snacks (maritime snails aren't hard to catch and big ones were always just a few minutes away). With the transition to agriculture, some people developed a tolerance to lactose (I'm fully lactose tolerant) and a gluten tolerance (me again). And it's a toss-up (there is no scientific certainty one way or the other) whether individuals with these tolerances can eat dairy products and grains as part of their evolutionary diet without any ill effects. But these tolerances were relatively recent, and there is no reason to think those with a tolerance would necessarily be healthier if they indulged their tolerance.
Some palaeo diet enthusiasts exclude from their diet all South American foods (and they even refer to them as "the nightshade family" to emphasize their exclusion of them): potato, capsicum, tomato, some aubergines. Personally I eat a lot of fresh tomatoes in summer/autumn but virtually none when they are not in season. (I also eat far more fresh fruit when it's in season.) On the other hand, I eat perhaps half a dozen small servings of potatoes over a whole year. I can't justify my choices of food varieties with a rigorous scientific rationale.
You ask if we should confine our eating to "... a palaeo diet based on the specific foods that our ancestors would have eaten?"
My answer would be "not strictly", but I think the key characteristic of the warm tomato I pick off the plant one summer's day is NOT the fact that it's a tomato as much as that it's fresh (minutes off the plant), naturally grown, and eaten as part of a natural vigorous lifestyle; my body is primed for the fresh food, rich in antioxidants and other micronutrients. A 21st century couch potato taking daily pharmaceuticals and smoking would derive a quite different nutritional effect from the same fresh tomato.
There is a further question of whether meat was cooked or eaten raw. I suspect both. Perhaps hunters drank blood (for symbolic as well as nutritional reasons) immediately after a kill.
The variation in quantity is also a key characteristic of palaeo eating. They had "all-you-can-eat" feasts after a productive hunt and days with nothing when hunting was not productive. Thoughtful palaeo eaters today do "intermittent fasting" by skipping meals (two meals a day with 12 hours between them), exercising on an empty stomach and not eating or drinking for an hour or more after exercise (this also happens to be the circumstances under which - all other things being equal - the body generates most Human Growth Hormone). Variety and unpredictability of physical activity and diet are as important as the actual palaeo foods eaten.
Variety and unpredictabilty were a part of life: there would have been good times and bad. Shivering at night - and even days on end - would have been common in winter. Living in a social group would have helped make the bad times more bearable. In the future, life will also be more unpredictable than it is today. Get used to not being used to things!
This reply has not answered all your questions directly, but I hope it's helpful nonetheless.
Congratulations on giving up smoking. It can only do you good. Cooking with a wood-fuelled fire will give you plenty of smoke pollution. Giving up smoking will enable you to derive a benefit from your coming break in the Australian bush which smoking would have nullified: inhaling with every breath clean air will do you the world of good. Clean air does not mean air devoid of everything other than molecules of nitrogen, oxygen, carbon dioxide etc. The air our ancestors breathed contained micro-organisms (bacteria, fungal spores), water vapour, natural volatile organic compounds given off by plants, fungi and other life (and no toxic VOCs given off by plastics). During the millions of years of human evolution our ancestors co-evolved with the air of temperate rainforest environments and its health-promoting effects are one of the most neglected in our increasingly prosthetic world. 150 years ago the most effective treatment for tuberculosis was to go to a place in the country where one would sit outside in the sun - the health-giving effects were not just the leaving behind of indoor, urban air, but also the immersion in natural air and inhaling it with every breath.
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