Are Cereal Grains a Double-Edge Sword for Humanity?

"Cereal grains as a staple food are a relatively recent addition to the human diet and represent a dramatic departure from those foods to which we are genetically adapted. Discordance between humanity's genetically determined dietary needs and his (sic) present day diet is responsible for many of the degenerative diseases which plague industrial man . . .

There is a significant body of evidence which suggests that cereal grains are less than optimal foods for humans and that the human genetic makeup and physiology may not be fully adapted to high levels of cereal grain consumption." - Lierre Keith, quoting Dr. Loren Cordain in her book, "The Vegetarian Myth"