I'm not an expert of any kind in regards to these issues.
I've read popular articles written by scientists ( not about "paleo diets" ) stating the commonly held belief among scientists that making suppositions based on evolution is rarely a reliable way of getting closer to the truth.
Archaeologists change their ideas about prehistoric historic people only slightly less often than the fashion industry changes clothing trends.
A popular idea among paleolithic dieters is that prehistoric people did not eat "carbs" so we probably "evolved" to be better off without it. Yet, there is this article that brings up the possibility that human beings were eating primitive breads as early as 30 thousand years ago
You get the picture, the ideas behind this popular diet just don't and likely can't have a solid basis in objectivity.
Luckily, people don't need to be certain of what happened in some world long past to get an objective idea of what is good to eat and what is not.
Just look at what paleo dieters say to eat and at what they actually eat. Look up the research on those foods and the quantities they are consumed in.
Personally, *subjectively*, with no expertise supporting my opinion at all, I think the paleo diet, like the atkins diet and raw foods diets do make some people feel better, at least for a while, because it motivates them to cut a lot of crap out. All 3 get people to get off dairy and cut down on starchy junk foods. IMHO, that doesn't make the rest of their beliefs true or the rules of their diets necessary.