Paleolithic man doubtless ate anything he could get his hands on that was even remotely edible, drank his water from streams, ponds, and probably even mud puddles as dogs do today. Of the many ways scientists have to unearth the actual diets of early ancestors, stable isotope analysis is probably the most accurate. Such analysis of ancient human remains show most were at least as carnivorous, if not more so, than foxes and wolves.
Compare and contrast our robust, nose-to-tail meat-eating Paleolithic forebears with today’s modern Paleo man, who drinks crystal-clear, reverse-osmosis-filtered, bottled spring water, wears five-toed Vibram shoes, wouldn’t be caught dead eating grain-fed beef, totes his almond-flour-based snacks, and always carries his baggie of nuts to nosh on.
Source: Are nuts Paleo? Paleolithic man would probably say no