Moreover, without cooking, the human brain (which consumes 20-25% of the body’s energy) could not keep running. Dr Wrangham thus believes that cooking and humanity are coeval.
In fact, as he outlined to the American Association for the Advancement of Science (AAAS), in Chicago, he thinks that cooking and other forms of preparing food are humanity’s “killer app”: the evolutionary change that underpins all of the other—and subsequent—changes that have made people such unusual animals.
Dr Wrangham disagrees [that eating meat gave hominids the energy they needed to evolve a larger brain]. When you do the sums, he argues, raw meat is still insufficient to bridge the gap. He points out that even modern “raw foodists”, members of a town-dwelling, back-to-nature social movement, struggle to maintain their weight—and they have access to animals and plants that have been bred for the table. Pre-agricultural man confined to raw food would have starved.
Start cooking, however, and things change radically. Cooking alters food in three important ways. It breaks starch molecules into more digestible fragments. It “denatures” protein molecules, so that their amino-acid chains unfold and digestive enzymes can attack them more easily. And heat physically softens food. That makes it easier to digest, so even though the stuff is no more calorific, the body uses fewer calories dealing with it.
Richard Wrangham is Ruth Moore Professor of Biological Anthropology, Curator of Primate Behavioral Biology, at Harvard. Listen to the audio interview (about 10 minutes long) on the Economist Website, too.