It’s not easy to explain the evolution of humans. The fossil record is limited, and ecological transformations have erased a lot of evidence. The prevailing theory among evolutionary biologists is known as “Man-the-Hunter.” It suggests that eating animals challenged humans to overpower and outsmart competitor species, travel long distances, and cooperate, which turned our great-ape ancestors into the lousy climbers with big brains that we are today. According to Harvard Professor Richard Wrangham, this isn’t the whole story. In his book
, he explains the “cooking hypothesis,” which contends that cooking is responsible for our large brains, our small mouths and guts, our division of labor, and our hairlessness.
It’s no modest proposal, but Wrangham’s tone is humble as he carefully distills hard science into digestible units, borrowing deftly from biochemistry, comparative anatomy, physics, and more. He ridicules the mystical accounts of human societies living without fire, all of them “equally full of fantasy”; he outlines the adaptability of human bodies to cooked food, and demonstrates beyond doubt that cooking increases the energy yield from all kinds of food. That high yield means our guts didn’t have to be as big as those of other mammals, and consequently that they didn’t use nearly as much energy — which means that our brains, which account for about one fifth of our overall energy consumption, were free to grow at unprecedented rates.
A 30-page bibliography attests to the depth of Wrangham’s research, and he is never short of colorful anecdotes. One man’s stomach, shot accidentally at short range, never fully closed up, and as a scientific subject (later the source of much resentment), he enabled a Michigan scientist to literally watch him digest his food. In later chapters, Wrangham boldly tackles more controversial matters. The division of labor resulting from men’s superior ability to hunt not only encouraged the development of family units without precedent in the primate world, but also meant that men were unconditionally “the greater beneficiaries” of the cooking revolution.
Wrangham closes with an epilogue on the insufficiency of nutritional science and the crapshoot that is finding a healthy diet in an industrialized world. It’s a call to arms, appropriately radical, yet sober, coherent, and rational. Wrangham’s revolution — be it recognized as such — is uniquely dignified. One might even say it’s highly evolved.