First of all, I'd like to share an especially interesting link given to me by my friend Elizabeth -- an interesting debate on the "paleolithic diet" from the perspective of four "experts" in various anthropologist and biology fields.
GOOD -- Ask the Experts: Is the "Paleolithic Diet" Really Better?
What I took away from this is that while the opinions were differing, there seemed to be a broad general agreement that one size does not fit all and that generalizations are often not factual.
"Leonard: In the modern, industrial world, we have become ever better at creating diets that are dense in calories and don’t require a lot of energy to procure them. No one recommendation is going to fit everybody, so the challenge is to find what works for you individually, and, at the same time, what fits the broad nutritional requirements of our species."
"Leonard: Although there’s an extraordinary range of variation, based on the climate and the environment, hunter-gatherers get a fair amount of meat in their diet. We require a diet that is more energy-dense than other primates and historically, we may have reached that point by incorporating more meat. It’s reflected in evolutionary changes in our face, our teeth, and in our gastrointestinal tract. Indeed, the GI tract of modern humans looks more like a carnivore's than a large primate's. Because early humans increasingly used tools to hunt, we don't show the same kinds of dental adaptations as modern carnivores."