Why do we share food?

"He places his human subjects, too, in an ecological network of "food webs" that vary massively over time as they develop from broad-based hunter-gathering strategies, which took in everything from big game to wild seeds, to an eventual narrowing of our dietary choices to those that can be serviced by settled agriculture. An evolutionary parallel to this process is drawn in his tale of the emergence of the big brain.

We, as we know and celebrate, have very big brains. This capital evolutionary gain comes at a certain cost. First off, our gut reduced in size and complexity to compensate for the over-development at the top end of our bodies; and second, we, and our mothers, needed extra nutrition to give ourselves a head-start. This had a galvanic impact on our eating strategies, putting an emphasis on group cooperation on the one hand, while limiting to a degree the sort of foods we once knew and loved."

A review of Feast: Why Humans Share Food by Martin Jones