Heard this yesterday in the car and had to go back and track it down for another listen. This is part of a series on NPR calls "The Human Edge". Intersting stuff, I think it makes a good case for low and slow cooked meats as "brain food" Give it a listen.
http://www.npr.org/blogs/health/2010/07/30/128877628/meat-fire-and-the-evolution-of-man
The whole thing is 7 mins 47 secs