UC Berkeley anthropologist specializing in diet: Meat-eating was essential for human evolution

It was this new meat diet, full of densely-packed nutrients, that provided the catalyst for human evolution, particularly the growth of the brain, said Katharine Milton, an authority on primate diet.

Without meat, said Milton, it's unlikely that proto humans could have secured enough energy and nutrition from the plants available in their African environment at that time to evolve into the active, sociable, intelligent creatures they became. Receding forests would have deprived them of the more nutritious leaves and fruits that forest-dwelling primates survive on, said Milton.