The author expounds some interesting ideas about how even the earliest transition of humans (homo sapiens) from a hunter-gatherer culture to a fixed farming culture has put us at odds with our evolutionary genetics; a disconnect that has grown substantially since the industrial revolution. He presents a very compelling argument for this during first two thirds of the book when discussing how humans are not genetically engineered for the high carbohydrate diet and relatively sedentary life style the the transition to agricultural communities brought about. He is, in my opinion, on shakier ground when he postulates various physiological and social downsides of this transition later in the book as he makes largely unsupported assumptions about the well being of humans in the hunter-gather cultures and over states the cause-effect relationship between such ills in modern society. This is apparent when he repeatedly is forced to use such language as “the evidence is scant” or “the little data available is intriguing.”
The conclusions at the end of the book about how we could have a healthier and happier future are at odds. He acknowledges that to go back to anything like the hunter-gather culture would be impossible without a drastic decrease in the world population. However, most of the impending problems he sees for our future would disappear with such a drastic population decrease, and without any changes to our current highly developed civilization that does provide a much better life for us all.