What are the biological and behavioral adaptations that allowed for the increase of human brain size? How has our diet changed over the past 2 million years, and how do we know?

What are the biological and behavioral adaptations that allowed for the increase of human brain size? How has our diet changed over the past 2 million years, and how do we know? From an evolutionary perspective evaluate the Standard American Diet. What are the impacts of this diet and how might we bring our diet in line with our evolutionary adaptations?