That isn't what the author said. The author said there was a temporary change in skeleton because the diet was lower in protein and farming was wearisome, meaning harder.
"When people make the transition from hunter-gathering to settled agriculture, their skeletons change - they temporarily grow smaller and less healthy as the human body adapts to a diet poorer in protein and a more wearisome lifestyle. Likewise, newly domesticated animals get scrawnier."
Good point. I read too hastily. However, most who have done any farming as most of us have experienced it didn’t fail to consume a large amount of protein. It may be that archeological evidence of ancient times establishes that there were cultures of farming where there were no animals raised for food and nothing such as eggs.