Humans also vary in their ability to extract sugars from starchy foods

 Humans also vary in their ability to extract sugars from starchy foods

 as they chew them, depending on how many copies of a certain gene they inherit. Populations that traditionally ate more starchy foods, such as the Hadza, have more copies of the gene than the Yakut meat-eaters of Siberia, and their saliva helps break down starches before the food reaches their stomachs.

These examples suggest a twist on “You are what you eat.” More accurately, you are what your ancestors ate. There is tremendous variation in what foods humans can thrive on, depending on genetic inheritance. Traditional diets today include the vegetarian regimen of India’s Jains, the meat-

intensive fare of Inuit, and the fish-heavy diet of Malaysia’s Bajau people. The Nochmani of the Nicobar Islands off the coast of India get by on protein from insects. “What makes us human is our ability to find a meal in virtually any environment,” says the Tsimane study co-leader Leonard.