Theories like that sound great, Paleo. But it may not really reflect what happened at all. We can pull all kinds of stuff out of our parts of the anatomy we sit on, but just because they sound "logical" to us, doesn't mean it happened that way. That's why we need anthropological evidence.
You're assuming that hunting was easier than gathering. It might have been at times when game, especially big game, was plentiful and dumb, but their may have been other times, and locations, where gathering was as easy as climbing a tree, picking fruit up off the ground, digging up a root, picking berries off a bush or smashing some nuts with a rock.
P.S. I was just teasing about my self-perception as a gatherer. I'm pretty sure I was probably the woman lounging on a rock supervising someone else and nagging the men to make themselves useful.
I really agree with much of the paleo philosophy due to how my body is rejecting so many of the products of modern agriculture, but I don't see a lot of objective evidence that man was ever solely carnivorous. The best evidence I have seen in modern HG, our closest animal cousins is that humans eat a lot of different foods and, in fact, do best when they have that variety available.
It is a little hard to compare though. Because we're living a lot longer than our uncivilized ancestors due to sanitation, improved child birth, disease control, insect control and stuff like that.
I don't think you can even point at the Innuit and say they lived longer on their diets, if I recall correctly, they tended to die pretty young.
Well... oops! I wasn't going to get dragged into a debate on the topic. And look what happened. Off to reform school with me.