Scientists of Melbourne said that carnivore (human) tend to have a bigger brain than herbivore (vegetarian) after you grow old. Although they never state what can you do with a big brain, but the bigger, the better, isn’t it?
(Link) to Times of India, (Link) to another China news.
Side note, I heard Albert Einstein has smaller than average brain. I also know human only “used up” 10% of our brain in a lifetime. There is also a debate going on whether turning all human to vegetarian will save the Earth.