fayfreethinkers.com

After two tremendous growth spurts — one in size, followed by an even more important one in cognitive ability — the human brain is now a lot like a teenage boy.

It consumes huge amounts of calories, is rather temperamental and, when harnessed just right, exhibits incredible prowess. The brain's roaring metabolism, possibly stimulated by early man's invention of cooking, may be the main factor behind our most critical cognitive leap, new research suggests.

About 2 million years ago, the human brain rapidly increased its mass until it was double the size of other primate brains.

"This happened because we started to eat better food, like eating more meat," said researcher Philipp Khaitovich of the Partner Institute for Computational Biology in Shanghai.

In most animals, the gut needs a lot of energy to grind out nourishment from food sources. But cooking, by breaking down fibers and making nutrients more readily available, is a way of processing food outside the body. Eating (mostly) cooked meals would have lessened the energy needs of our digestion systems, Khaitovich explained, thereby freeing up calories for our brains.

Today, humans have relatively small digestive systems and burn 20-25 percent of their calories running their brains. For comparison, other vertebrate brains use as little as 2 percent of the animal's caloric intake.

Does this mean renewing our subscriptions to Bon Appetit will make our brains more efficient? No, but we probably should avoid diving into the raw food movement. Devoted followers end up, said Khaitovich, "with very severe health problems."