The author has a strong tendency to draw the wrong conclusion from a piece of presented information. In almost every example, something other than agriculture is obviously to blame for the problems described.
I stopped reading at the example about the teeth of Native Americans. They say agriculture was a response to a growing population... Overpopulating to the point of making hunting unsustainable was the mistake.
This was right after the example of the agricultural area of Greece (or somewhere, I forgot) being shorter than their neighbors. As if health was measured in height??