Evolutionary effects of cooking: The impact of fire in human evolution

Richard Wrangham, Department of Anthropology, Harvard University

Although Darwin considered the control of fire “probably the greatest [discovery], excepting language, ever made by man,” he implied that the use of fire was a purely cultural achievement and he did not explain what made it important. I propose that humans are biologically adapted to the control of fire, because it enables the cooking of food, which leads to large amounts of energy. Evidence of compromised physiological performance among individuals on raw diets supports the hypothesis. Mechanisms contributing to net energy gain from cooked foods include increased digestibility of starch and protein, and reduced costs of digestion eating cooked versus raw meat. Humans differ from other great apes by having reduced digestive systems, modified as a consequence of the availability of processed food. Contemporary evidence indicates that humans are not adapted to raw diets, while fossil evidence suggests that humans have been cooking since Homo erectus. Darwin underestimated the impact of the control of fire, since it now appears responsible for the origin of Homo erectus.