by Richard Wrangham, as told to Discover’s Veronique Greenwood. Wrangham is the chair of biological anthropology at Harvard University, where he studies the cultural similarities between humans and chimpanzees—including our unique tendencies to form murderous alliances and engage in recreational sexual activity. He is the author of Catching Fire: How Cooking Made Us Human.
When I was studying the feeding behavior of wild chimpanzees in the early 1970s, I tried surviving on chimpanzee foods for a day at a time. I learned that nothing that chimpanzees ate (at Gombe, in Tanzania, at least) was so poisonous that it would make you ill, but nothing was so palatable that one could easily fill one’s stomach. Having eaten nothing but chimpanzee foods all day, I fell upon regular cooked food in the evenings with relief and delight.
About 25 years later, it occurred to me that my experience in Gombe of being unable to thrive on wild foods likely reflected a general problem for humans that was somehow overcome at some point, possibly through the development of cooking. (Various of our ancestors would have eaten more roots and meat than chimpanzees do, but I had plenty of experience of seeing chimpanzees working very hard to chew their way through tough raw meat—and had even myself tried chewing monkeys killed and discarded by chimpanzees.) In 1999, I published a paper [pdf] with colleagues that argued that the advent of cooking would have marked a turning point in how much energy our ancestors were able to reap from food.
To my surprise, some of the peer commentaries were dismissive of the idea that cooked food provides more energy than raw. The amazing fact is that no experiments had been published directly testing the effects of cooking on net energy gained. It was remarkable, given the abiding interest in calories, that there was a pronounced lack of studies of the effects of cooking on energy gain, even though there were thousands of studies on the effects of cooking on vitamin concentration, and a fair number on its effects on the physical properties of food such as tenderness. But more than a decade later, thanks particularly to the work of Rachel Carmody, a grad student in my lab, we now have a series of experiments that provide a solid base of evidence showing that the skeptics were wrong.
Whether we are talking about plants or meat, eating cooked food provides more calories than eating the same food raw. And that means that the calorie counts we’ve grown so used to consulting are routinely wrong. Read More