Human brain is extremely energy expensive. Although a human brain is only 2% of our total body weight, it consumes 20-25% of our total energy need. Most other primates can barely gather enough food for survival, let alone growing an energy hungry brain. So how did our ancestors do it? According to Suzana Herculano-Houzel, it was the invention of cooking: Cooking allows foods to be easily digested and absorbed. So our ancestors were able to gain much more energy from the same amount of food.
In short, our ancestors may not never evolved they way they did without “cooking”
Listen to the following:
A few of you may have already read about this, and I believe it may have been posted on Chowhound. Still I think it is a nice story.