Anthropologist: One of the distinctive traits of humans is the ability to support a large brain with a small gut, which requires getting more calories from less food  It was likely the development of cooking that made this possible  After all, our ancestors developed large brains around the time that they began to control fire
And even today, people who choose to eat only raw food have difficulty getting enough calories
The human body uses more calories to process raw food than it uses to process cooked food.