Sunday Times review by James McConnachie, 27th September 2009

This is a daringly unorthodox book, and one that might just transform the way we understand ourselves. Richard Wrangham believes that humanity evolved not because of hunting or using tools — as most other academics seem to think — but because of cooking. And he is willing to step outside the scientific mainstream in order to prove it.

The birth of cookery is usually dated to about 200,000BC, when charred­hearthstones, burnt bones and the like start appearing in the fossil record. But Wrangham is a Harvard professor of biological anthropology, not an archeologist, and he uncovers the best evidence of ancient cookery not in ashes but in our own anatomy. Controversially, he finds it an astonishing 1.9m years in the past, at the very moment when our ancestors made the great evolutionary leap from ape-like australopithecine to tool-wielding Homo erectus: the moment when we became, near enough, ourselves.

It wasn’t just a matter of standing up straighter. At this time, our guts, mouths, teeth and jaws all shrank to their current size — pathetically weak, by primate standards — while our brains swelled. The best explanation for this remarkable double transformation, Wrangham argues, is that we learnt to cook. Digesting and thinking both burn energy like a 4x4 with the air conditioning on. In fact, the fuel in one in five of an inactive person’s meals is solely consumed by their brains. Cooking, however, gives digestion a head start: it gelatinises starch and denatures protein, breaking down our food even before we eat it. So down the generations, cooking allowed early humans to evolve smaller but less energy-consuming digestive systems, which in turn freed up crucial calories for use by the brain. We traded intestines for brain cells and, as a result, became evolutionarily wedded to fire.

Wrangham finds his most powerful argument in a curious place: within the raw food movement. To a surprising number of people, “raw” equates with “natural” or even “more powerful”. Take the raw eggs beloved of celebrity strongmen: Charles Atlas devoured them in fistfuls; Arnold Schwarzenegger ate them with cream; Sly Stallone scarfs them in Rocky. Yet eggs turn out to be less calorific raw than cooked. Then there is the raw-food ideology of vegan-naturopath types, who believe that unheated foods preserve some inner “life energy”. But in the words of the authoritative Giessen Raw Food study, a raw-food diet “cannot guarantee an adequate energy supply” and, shockingly, about half of female raw foodists are so thin that they stop menstruating. This has nothing to do with any nonsensical notion of “detoxification” or life force, and everything to do with near-starvation.

In one delightful anecdote, Wrangham lunches with three extreme self-proclaimed “genefit” raw-foodists who eschew not just cooking but the mixing of different foodstuffs, on the basis that this is what works for foraging primates. They politely decline a chopped salad and tuck in, respectively, to apples, a pineapple and a delicacy that “looked like strawberry ice cream” — but turns out to be the marrow in golf-ball-sized chunks of buffalo femur. It is eaten with a teaspoon.

The eccentricity might be splendid if it didn’t rest on what Wrangham believes is a deep-seated misconception of who we are. We are not your ordinary primate, and Wrangham should know: he has spent 30-odd years studying chimpanzees in the wild. When he observes that some chimp delicacies “taste so foul that I can barely swallow them”, it not only reveals impressive dedication to research, it demonstrates that humans have developed puny digestions capable of being upset by the mildest of toxins.

Wrangham has even tried adding leaves to raw meat, as chimps do, to see if it speeds up chewing. He finds that it does, and this is no side issue. Chimpanzees chew for six jaw-aching hours a day and this is time and energy they cannot spend hunting. Indeed, our dislike of mastication seems to have become embedded in our very biology, as we almost universally prefer the feel of soft foods, and will go to extraordinary lengths to source them. Western cuisine fetishises foie gras, for instance, while Marco Polo claimed that Mongol horsemen who could not stop to light a fire would put steaks under their saddles and ride them into warm tenderness. Even those huntergatherer societies that lack pots prefer to cook. They use stones as griddles, earthen pits as ovens, lengths of bamboo as steamers, or shellfish and turtle shells as ready-made ramekins. Australian Aborigines scramble emu eggs by throwing them in the air, then putting them in hot sand. Traditional Inuit groups, much touted as consumers of raw fish and whale meat, actually prefer to boil their dinner over seal oil fires, however slowly they burn.