CATCHING FIRE

An innovative argument that cooked food led to the rise of modern Homo sapiens.

Wrangham (Biological Anthropology/Harvard Univ.; co-author: Demonic Males: Apes and the Origins of Human Violence, 1996, etc.), the curator of Primate Behavioral Biology at the Peabody Museum, begins by demolishing the fashionable raw-food movement. Despite claims that raw food is the natural human diet, the author finds no culture, however primitive, that doesn’t cook. Studies show that a pure raw-food diet provides adequate nutrients but insufficient energy; subjects lose weight and half the women stop menstruating, a sign of malnutrition. Compared to apes, our gastrointestinal tracts (lips, mouth, jaws, teeth, stomach, colon) are tiny. The reason, he asserts, is that cooked food is calorie-dense, soft and easy to digest. Searching for and consuming food occupies most of the day for all primates except humans. Chimps spend six hours per day chewing, humans about one. Searching the fossil record, Wrangham describes earlier hominids, pinpointing the cooking revolution at the appearance of our direct ancestor, Homo erectus, in Africa 1.8 million years ago. “Cooking was responsible for the evolution of Homo erectus,” he writes. Many anthropologists focus on its larger brain, larger body size and more stable upright posture. Wrangham emphasizes its smaller teeth and narrower rib cage and pelvis, which indicate a smaller gut. Sadly, the author concludes, modern, sedentary humans get fat, not because our bodies remain adapted to the constant threat of starvation but because we love our calorie-rich diet. Apes in captivity don’t grow fat unless fed cooked food.

Experts will debate Wrangham’s thesis, but most readers will be convinced by this lucid, simulating foray into popular anthropology.