Body Slim Down The Paleo diet was popularized by a gastroenterologist named Walter L. Vorgtlin in the 1970s, and was named so because it includes food that was most available during the Paleolithic era. This diet is not just based on copying what humans ate in the Paleolithic era, but also on real non-partisan science and evidence. The food that our ancestors consumed made them stronger, slimmer, taller and faster than we are.