Isotopic analysis of early hominin teeth suggests a more carnivorous diet preference, with early Homo habilis exhibiting isotopic ratios similar to carnivores.

“you can see a clear pattern toward a more carnivorous preference as we move from Australopithecus afarensis to Paranthropus to Homo habilis about 1.8 years ago and that's when we started hunting so you can look at these graphs maybe we'll put one of them on the screen you can see that the ratios of early homo habilis 1.8 million years ago these isotopes are essentially carnivorous and there's a clear pattern Australopithecus afarensis eating more animal foods than grazers and browsers and then parent throw up us eating a little more and then the early homo homo habilis eating basically as much animal food as carnivores and clearly trending toward eating more animal foods at 1.8 million years ago”