The study, suggests that after we started consuming meat, we no longer needed the large digestive gut and could then put that energy consumed toward making our brains larger. This also changed the way our teeth began to look, instead of having sharper teeth, we began to have large, round teeth instead. This not only helped make chewing up meat easier but vegetables as well. How exactly our species discovered meat is unclear, however it seemed to begin a civilizing process that has continued though to today.
Obviously there is more involved in the evolutionary story than just discovering meat and getting smarter, we also had to learn to cook it. This isn't to say that eating raw food is less healthy than not, only that cooking food makes it easier to digest. So we cook meat, we have more energy, and according to this study we're smarter for it (or rather because of it) but whether it is right or wrong still remains in question. According to history, it was right to eat meat because it led to making better tools, smaller guts and eventually a civilized world. Eating meat now is not quite the same as it was during our evolution, as most of our guts have come back, but if it does help us grow "bigger" brains as this study suggests, why not choose to eat meat?