want to eat like a caveman? eat grains and legumes
I recently mentioned a study showing that dietary intake of fiber from grains was strongly tied to lowered risk of death from cardiovascular, infectious, and respiratory diseases, and also protective against cancer deaths in men. (That intake would have to be mostly from whole grains, since the whole point of refining grains is to remove the fiber-rich bran.) And I mentioned that this was another strike against the "paleo" diet, which strongly discourages consumption of grains, as well as legumes and tubers.
Followers of the paleo fad argue that their diet is optimal because it represents what humans ate before the development of agriculture. But as it happens, for years we've had evidence that consumption of wheat and barley -- and perhaps even grain-flour bread -- goes back at least 23,000 years. (And there are hints that it might go back as far as 105,000 years, but that's still very speculative.)
And more recently, in an analysis published in the Proceedings of the National Academy of Sciences researchers from George Washington University and the Smithsonian Institution examined phytoliths (microscopic bits of silica or other minerals from plants) and starch grains found on Neanderthal teeth dating back 36,000 to 46,000 years. Their research shows that these most iconic cavemen (who have been recently shown to be part of our ancestry and not just an evolutionary dead-end, as was argued for some years) were not only eating legumes and grains like barley, but were cooking these carb-rich foods to improve their digestibility. (Full article here, though it may be hit by the copyright cops at some point.)