I know that the core Paleo principle is about eating foods which were available to us in the paleolithic era and I would like to understand this principle a little better since there can be so many variables involved in defining our adaptation to certain foods. I have tried google with ALL KINDZ A queries with zero results, anyone have resources or answers? Also why are there so many healthy super centenarians who eat non paleo foods like the sardinians, okinawans and costa ricans of the Nicoya peninsula? Surely these cultures have adapted to these foods enough to live such long lives, what's the paleo defending argument for this case?
There is no argument, as girlgenius said. The point of Paleo is health NOW. Not what might hypothetically happen when you're 100. So far as adaptation goes I think more or less immediately, certainly within a week. If you can't digest it, whatever it is, eat something else.
I am not sure where and when the paleo diet went off course.... But the paleo diet is not about reenactment. Some quacks are trying that now to very limited success. Paleo is about finding optimal health. We tend to believe that the best way to go about it is by looking through the lens of evolution to frame hypotheses -- but it is a fallacy to believe that everything paleolithic is healthy and everything neolithic is not. It is also a fallacy to believe that anything that is alive today is comparable to what was around in paleolithic times. Moderns incarnations of Chicken, Beef, Fish, Crustaceans, Vegetables, Seeds, Fruits -- virtually none of this was available to the paleo man.
Dr Harris put it besy, paleo is a, "central thesis is that certain aspects of current ill health are due to behaviors that are substantially outside our evolutionary experience" (read more: http://www.archevore.com/panu-weblog/2009/11/26/the-paleolithic-principle-the-panu-version.html)
As for the civilizations that you mention -- their diet is probably closer to an acestral diet that most people who follow a paleo template. Also, diet is only part of it -- their lifestyle far more closely follows ancestral behavior than most of ours do (@thhq excluded).
Should be a little more explicit in your first question. Certain foods and adapting...hmm? The whole point of paleo is that we did not adapt to foods...so, not really sure what you're looking for. If you're talking about macro ratios in particular, E.G. adapting to fats where adapting = processing them efficiently you may find it easier to find an answer.
On your second question, I don't know much about specific cultures, but centenarians in general are oddities, exceptions. For example, if a centenarian smokes and drinks and lives till 200, should you? Probably not, that being said there is probably something worth learning from them, but what is it? How sure are you their diets are the main factor? Could just as eaily be genetics, or enviornment, specifically lack of pollution or toxins, or mentality and stress levels. ( Food for thought )
On another note: I completely disagree with everything Girlgenius said.
Paleo doesn't bother to defend against centenarian cultures who live today. We are interested in living a Paleo life. That's our interest, that's what our discussion forum is about. It's great that there are healthy diets in the world, but it's not interesting to me, personally. My ketogenic and Paleo diet is working for me, thanks.
If I understand your question, you're asking how long it would take, in geologic or evolutionary time to properly digest foods that are non Paleo (like legumes for example). The fact is, we can digest them now.
BUT ONLY IF we properly prepare them through a long process of soaking and/or fermenting and/or sprouting. Paleos say, why bother? This is too much effort after we have already used fossil fuels to cultivate and harvest them, used massive amounts of water to grow them... etc etc.. This is a waste when we can pasture some animals and eat them with much less effort. Technically, some of us believe that it is even simpler to hunt for our food. Or at least hunt for some of our food. Or fish.
There is no need for defending arguments. This is what we do.