Doesn't natural selection sort of assume that you get killed off before you breed? I think the problem of adapting to carbs is that it tends to make problems after your reproductive years, for the most part. Some carb problems, like PCOS, keep women from being fertile, so perhaps that will get bred out eventually.

Then again, I don't really think carbs are the whole story. I think its carbs in combination with lack of physical activity. And I don't mean a trip to the gym everyday, I mean.... physical labor each day. Cars, desk jobs and the whole lot keep us from using up the glucose.

That part of the equation is new, really only in the last 50 years or so we've gotten to this level of indolence.