Yes. Could be both. The problem is the simpler, 'meat' based answer, leads people to say "Brains grew big because eating meat, I think I'm going to pull up to

Yes. Could be both. The problem is the simpler, 'meat' based answer, leads people to say "Brains grew big because eating meat, I think I'm going to pull up to the table and down a few pounds of ribs and wash it down with a nice brisket".