Ever wondered what really made us human? Most evolutionary anthropologists will point to the social culture of hunter-gatherers and eventually the advent of agricultural domestication. Richard Wrangham proposes an entirely different perspective: thanks to the discovery of cooking, we saved time otherwise spent on hunting, gathering and chewing raw food and spent on other, intellectually challenging activities, instead. This gradually increased our cognitive abilities until we began organizing social culture around cooking. And so human culture was founded.

Apparently, the idea that cooking was the crucial difference between their diet and ours came to Wrangham as he stared into the fire at home. Though there's no archaeological evidence of controlled fire before 800,000 years ago, he realized that a cluster of changes in the human face, brain, and gut 1.8 million years ago could be explained by only one thing—regular cooked meals. His argument begins with the odd spend-money-to-make-money aspect of digestion: You must burn calories in order to release calories from food (a fact deeply cherished by celery-chewing teenage girls). Because raw food is harder to digest, it takes more calories to get the calories out of it, and you get fewer calories from it anyway.

Wrangham illustrates this with an array of observations and experimental evidence. He cites a BBC TV show about an "Evo Diet Experiment" that followed nine volunteers who gave up processed food for 12 days and ate only the kinds of food that humans are supposedly wired to eat, mostly raw nuts, fruits, and vegetables. At the end of the experiment, the volunteers had improved cholesterol and blood pressure, and they also lost a lot of weight, despite the fact that the food was chosen to give them the required amount of calories per day. Wrangham even meets with some modern-day raw foodists, who are all very slim. He finds ample evidence that people who eat mostly raw food "thrive only in rich modern environments," and they usually feel very, very hungry. An actual "evo" diet, Wrangham notes, would deliver even fewer calories; require some actual hunting and gathering; and, being more like the diet of chimps, need to be chewed for hours and hours every day.

Cooked food, by contrast, is easier to digest, gives you more energy, and takes no time to eat. Cooking also kills bacteria and renders many natural poisons inactive. So the simple expedient of heating food gave us access to many more safe calories every day, which was a survival jackpot. Once we started to eat soft, cooked food, our jaws and teeth were no longer required to munch ceaselessly, and they became smaller and more delicate. That is why we don't look like apes anymore. Similarly, the more cooked food we ate, the less industrial-strength digestion we had to do, and the smaller our guts became. In the same way that our bodies evolved to better walk on two legs, our bellies changed to better handle well-done over rare. This had two enormous payoffs. First, as our guts got smaller, this freed up energy for our brains to operate on a larger and larger scale. (Leslie Aiello and Peter Wheeler first discovered the relationship between gut size and brain size, dubbing it the Expensive Tissue Hypothesis.) Second, as we spent less time eating, we had more time to do other things with those rapidly expanding brains.

The real issue here is of course the cause-effect dilemma; Wrangham needs to find solid evidence that we began cooking much earlier on in human history than previously believed. The fact that we are hardwired to mostly survive on a paleo-diet is already known and doesn't necessarily support his thesis. So what can we possibly learn from his theory?

Cooking food has obviously saved us time, and still does. Yet, depending on how you prepare your food, there are both costs and benefits. Ordering home pizza might save you time compared to, say, preparing a chicken salad, but you will also spend more money on eating less healthy food. Today we lead busy lives, but I doubt the activities with which we replace cooking time amount to serious cognitive development. In fact, we're rapidly losing knowledge of how to clean fish, how to prepare meat, how to make salads etc. We're losing thousands of years of practical cultural wisdom.

Therefore I propose a cooking revolution, which suggests we need to spend more time in the kitchen, and preferably make it a social activity again like in ancient times. I know I'm not alone. Why not celebrate both the ancient art of cooking and the recent advent of beer by preparing this tasty-looking beer can chicken recipe by Wendy Cooper?