Hominin Meat Eating As Early As 1.5 Mya

Science Daily has a story detailing evidence that early hominins (and by this I mean probably Homo habilis or Homo ergaster) eat meat.  Although it is almost in the form of negative evidence. They write:

The two-inch skull fragment was found at the famed Olduvai Gorge in northern Tanzania, a site that for decades has yielded numerous clues into the evolution of modern humans and is sometimes called `the cradle of mankind.'

The fragment belonged to a 2-year-old child and showed signs of porotic hyperostosis associated with anemia. According to the study, the condition was likely caused by a diet suddenly lacking in meat.

"The presence of anemia-induced porotic hyperostosis…indicates indirectly that by at least the early Pleistocene meat had become so essential to proper hominin functioning that its paucity or lack led to deleterious pathological conditions," the study said.

This is common in dietarily compromised populations today.The general consensus is that hominins' brains expanded when they began incorporating meat into their diet, although it has been commonly thought that that did not occur until Homo erectus, for which there is direct evidence of hunting.