Meat Made Us Smarter ...and learning how to cook it made us human By Jane Yager, Newser Staff Posted Aug 2, 2010 6:34 AM CDT Updated Aug 7, 2010 7:00 PM CDT 64 comments Comments A student prepares to do a French cut on a rack of lamb at Ryan Farr's butcher class in San Francisco, Tuesday, June 29, 2010. First we started eating meat, then we got smart enough to cook it. (AP Photo/Eric Risberg) (Newser) – Sorry, vegetarians: Humans have meat to thank for the evolutionary changes that made us the large-brained tool-users we are today. Some 2.3 million years ago, our ancestors made the jump from gnawing all day on leaves and nuts to scavenging carcasses. This, anthropologists say, was the magic moment when our brains got enough energy to start growing to their current size—largely because we no longer had to maintain a giant gut capable of processing all those raw leaves. From there came the invention of tools—"external teeth" that meant we didn't need big sharp teeth like other predators—and fire for cooking, which made meat easier to digest and squeeze nutrition from, meaning we no longer had to spend hours a day chewing like chimps do. Cooking also taught us to share labor and brought people together for conversation in the evening, making us even more human, NPR reports.