Rather than try to tie ourselves to a single diet that we're convinced is in line with the healthiest of our hypothetical ancestors, we should probably just do what our actual ancestors did: eat a variety of foods. We evolved to be omnivores, but most importantly we evolved to eat whatever was easiest to eat. Today, of course, the danger is that it's very easy to eat very unhealthy food. But that doesn't mean there's one natural, original diet we should all harken back to. Eat a little bit of everything—plants, animals (if that's what you're into), whatever—and eat it in moderation. Stay active, avoid tons of processed food, and you'll be just fine.