How do we humans fuel our big brains?

Half a million years ago, the human brain started expanding. Bigger brains need more energy to keep trucking, but scientists have been stumped as to where we found this extra juice when our metabolic rate, which is how we churn out energy, is on par with our pea-brained cousins.

One recent theory suggests that our brain's need for energy was fed by a smaller gut, since an easier-to-digest diet would free up energy from the gut to build up the brain. New research suggests this might not be the case, that storing energy in our fat deposits is more important.

" Animals with big brains, they had very low adipose (fat) tissue. Animals that had large adipose tissues had smaller brains," study researcher Ana Navarrete, of the University of Zurich, in Switzerland, told LiveScience. "Either you have a much (bigger) brain or a lot of adipose tissue. Usually they are mutually exclusive." ...


Reference:
Nature (2011) doi:10.1038/nature10629
Energetics and the evolution of human brain size
Ana Navarrete et al.