The art of mechanics came from the need for bread. It was the quest for bread that engendered industry. From Sundance Health Food's web site That is because bread goes back with us a very, very long way. But Man can't live on meat alone, nor on the pagan protections of Mother Earth and Father Sun. The human diet depends on Protein, Starch, and Fat.
Protein is a volatile fuel - our bodies use it right away, and then, it's gone.
A Protein diet is a perishable, perilous prey, requiring new meat every day, and a new hunt, and flight from the seasons. How impermanent, how ephemeral our ancestor's lives must've been, at mercy to the whims of the season, the herd, and the hunt. Starch can be stored in the body. Yet, it stays in the body until it is needed. It is the investment in the growth of grains that sowed the seeds of civilation.