Paleo's basic premise is loosly based on the malnourishment seen when we transitioned from a diverse hunter-gatherer diet to a much less diverse agricultural diet (largely caused by iron deficiencies). Its a misunderstanding of history. We ate those foods before, but they weren't the ONLY things people ate. The result is ultimately still restricting diet to healthier foods which means it's nutricious, but still unnecessarily restrictive and without a realistic premise.