Cooking was not an accidental discovery made when one of our ancestors started waving around a blazing branch. It wasn’t the case that our ancestors just picked up the trick of playing with fire whilst on their journey towards becoming home sapiens. Quite the opposite: cooking with fire is what drove our evolution from apelike habilines to modern people. That is the claim in this 2009 book by Richard Wrangham, a professor of Biological Anthropology at Harvard University.
The evidence is convincing. Apes have snout-like mouths which are ideal for chewing leaves and roots. Some apes, like chimpanzees, do eat meat, but when they do so, they don’t eat the whole animal. They concentrate on the soft parts like the brain, liver and kidneys. Even when eating vegetables, Wrangham estimates that chimpanzees spend about five hours a day just chewing their food.
Cooking didn’t just save us time, it also increased our brain size. Cooked food created energy savings because we needed less time to digest our food, and so we were able to reduce the space needed for intestines. These energy savings facilitated a quantum leap in the evolution of our cerebral matter:
How animals with small guts make use of their energy savings depends on what matters for them. In primates, the tendency to use energy saved by smaller guts for added brain tissue is particularly strong, presumably because most primates live in groups, where extra social intelligence has big payoffs.
Furthermore, the presence of fire enabled our ancestors to move down from the trees and live on the ground, because a fire would provide protection from predators at night such as lions and wolves. Thus we could evolve to become upright walkers, less able to climb trees, but better able to cover large distances whilst hunting or gathering fruit and vegetables.
By contrast, some people today argue that our natural diet would be one based on raw food. For them, cooking is a type of poison, creating or releasing carcinogens. This has led to far-out ideas like the raw food diet, a concept that Wrangham swiftly skewers through his analysis of the cost benefits of cooking:
the subjects of the Giessen Raw Food study obtained their diets from supermarkets. Their foods were the typical products of modern farming—fruits, seeds, and vegetables all selected to be as delicious as possible. “Delicious” means high energy, because what people like are foods with low levels of indigestible fiber and high levels of soluble carbohydrates, such as sugars … [supermarket] carrots contain as much sugar as the average wild fruit eaten by a chimpanzee
What sets Wrangham’s book apart from the sort of dull scientific texts that are forced on undergraduates (and which make you wonder why we bothered to come down from the trees at all), is his knack for using witty analogies.
Imagine going to a sporting event with sixty thousand seats around the stadium. You arrive early with your grandmother, and the two of you take the first seats. Next to your grandmother sits her grandmother, your great-great grandmother … The stadium fills with the ghosts of preceding grandmothers. An hour later the seat next to you is occupied by the last to sit down, the ancestor of you all … you turn to find a strange nonhuman face. Beneath a low forehead and a big brow-ridge, bright dark eyes surmount a massive jaw. Her long muscular arms and short legs intimate her gymnastic climbing ability. She is your ancestor and an australopithecine
A short book but a fascinating one, Catching Fire is an essay which challenges our preconceived notions of human evolution. In addition, Professor Wrangham also deconstructs and exposes the flaws in such things as those calorie counters that you see on food packaging. He has recipes for solving our health and obesity crisis, so that Catching Fire is not just about the past, but it also lays out public health solutions for the future too.