The discovery of cooking and the ability to obtain calories easily are now seen as the major event that triggered our brain enlargement, leading to the emergence of modern humans and our subsequent dominance of the planet. Our large brains are greedy and consume about 300 calories a day, even when we aren’t using them much. This is roughly equivalent to the energy of a weak light-bulb, and we can’t turn it off – the energy we use up when we are asleep is nearly the same.
