It's **what we did** with fire that made us human

A new theory suggests that if we had not learned to cook food, not only would we still look like chimps but, like them, we would also be compelled to spend most of the day chewing. It's well known that fire breaks down proteins and makes them easier to digest, so cooking rather than warmth, may have been a key in fire's power, especially for brain growth.

So, what's for dinner, homo habilis?