Jaques and the list, <<Are all the primates, except man, able to do that? "Man not being able to "naturally" balance it`s diet", Is that a preconception or a proven fact? Is all this in relation with "the production of opiate-like substances during the cooking process"? Are there any other reasons? Are there any recent papers on the subject?>> This is a very interesting topic. I think that the premise that man cannot balance its diet "naturally" comes from watching nineteenth and twentieth century man. We don't have any people left who are living lives totally unaffected by the twentieth century. Certainly our cultures have affected us. Acculturation might be responsible for this phenomenon of people not eating a natural diet. The western cultures have had many millenia of acculturation, as have many oriental cultures. Once a culture adopts agriculture, the elite have preferential access to the crops -- even if this results in poor health. Sorry, I don't have any references to cite, although i've seen discussions in some nutrition texts about oriental cultures. Their elite people, who ate white (polished) rice, had relatively poor health, while poorer people in the society ate unpolished brown rice and had much better health because they were consuming the B vitamins that the elite had polished off. As an anthropologist, I think it is culture that results in this type of behavior. So, perhaps one question that we should ask is: "is cultural pressure strong enough to overcome instinctual eating patterns in humans?" I would argue yes, it is -- particularly over long periods of time. Linda Scott Cummings, Ph.D. Paleo Research