Human like creatures have existed on this planet

Human-like creatures have existed on this planet for as long as four million years, and for roughly 99 percent of this time, they were hunters and gatherers…. This means that when we’re sitting down to lunch, our stone-age bodies "expect" to be fed the same types and ratios of fat that nourished our cave-dwelling ancestors.  When we eat French fries cooked in partially hydrogenated vegetable oil instead of wild plants; or wolf down a fat-laden hamburger heaped with mayonnaise instead of meat from a lean, free-ranging game animal, our bodies register the insult.  ~Artemis P. Simopoulos and Jo Robinson, The Omega Diet, 1999