“Cooked food does many familiar things,” he observes. “It makes our food safer, creates rich and delicious tastes and reduces spoilage. Heating can allow us to open, cut or mash tough foods. But none of these advantages is as important as a little-appreciated aspect: cooking increases the amount of energy our bodies obtain from food.”

He continues: “The extra energy gave the first cooks biological advantages. They survived and reproduced better than before. Their genes spread. Their bodies responded by biologically adapting to cooked food, shaped by natural selection to take maximum advantage of the new diet. There were changes in anatomy, physiology, ecology, life history, psychology and society.” Put simply, Mr. Wrangham writes that eating cooked food  whether meat or plants or both made digestion easier, and thus our guts could grow smaller. The energy that we formerly spent on digestion (and digestion requires far more energy than you might imagine) was freed up, enabling our brains, which also consume enormous amounts of energy, to grow larger. The warmth provided by fire enabled us to shed our body hair, so we could run farther and hunt more without overheating. Because we stopped eating on the spot as we foraged and instead gathered around a fire, we had to learn to socialize, and our temperaments grew calmer.

There were other benefits for humanity’s ancestors. He writes: “The protection fire provided at night enabled them to sleep on the ground and lose their climbing ability, and females likely began cooking for males, whose time was increasingly free to search for more meat and honey. While other habilines”  tool-using prehumans  “elsewhere in Africa continued for several hundred thousand years to eat their food raw, one lucky group became Homo erectus  and humanity began.”

You read all this and think: Is it really possible that this is an original bit of news? Mr. Wrangham seems as surprised as we are. “What is extraordinary about this simple claim,” he writes, “is that it is new.”

Image Richard Wrangham Credit... Tim Laman

Mr. Wrangham arrives at his theory by first walking us through the work of other anthropologists and naturalists, including Claude Lévi-Strauss and Darwin, who did not pay much attention to cooking, assuming that humans could have done pretty well without it.