A BBC article about research that asserts that our learning to cook food, as a species, was central to our evolution.
Without cooking, an average person would have to eat around five kilos of raw food to get enough calories to survive. "Cooking made our guts smaller," he says. "Once we cooked our food, we didn't need big guts."
Cooking food breaks down its cells, meaning that our stomachs need to do less work to liberate the nutrients our bodies need. This, says Wheeler, "freed up energy which could then be used to power a larger brain. The increase in brain-size mirrors the reduction in the size of the gut."