Right now, one half of all Americans are on a diet. The other half just gave up on their diets and are on a binge. Collectively, we are overweight, sick and struggling. Our modern choices about what and how much to eat have gone terribly wrong. The time has come to return to a more sensible way of eating and living, but which way? An entire class of self-help books recommends a return to the diets of our ancestors. Paleolithic diets, caveman diets, primal diets and the like, urge us to eat like the ancients. Taken too literally, such diets are ridiculous. After all, sometimes our ancestors starved to death and the starving to death diet, well, it ends badly. The past was no panacea; each generation we made do with the bodies and foods available, imperfect bodies and imperfect foods. Yet, the idea that we might take our ancestral diet into consideration when evaluating the foods on which our organs, cells and existence thrive, makes sense. But what did our ancestors eat?...