That period is when cut marks on animal bones appeared — not a predator's tooth marks, but incisions that could have been made only by a sharp tool. That's one sign of our carnivorous conversion.By eating meat, our brain, which uses about 20 times as much energy as the same size muscle, thrived. Calories and fat from meat allowed our bodies to put more energy into brain development. Our brains grew, we started using tools and cooking and the rest is, well, history.
There are plenty of detractors to these theories--see the comments after the article, but to me, it makes sense. What do you think?