This story has been kicking around for a few days already, but here's quite a nice take on it with some nice linked sources:

Tooth Chemistry Confirms Early Homo Loved Meat | Hominid Hunting


... these results suggest earlier hominids were generalists, and then around two million years ago, they began to specialize more. The addition of meat in Homo‘s diet may have allowed our ancestors to evolve big brains, which require a lot of energy to support.