Recently read Sapiens. Just for perspective, I would like to know if there are any theories, opinions, etc. which advocate some different/opposing ideas. (like say communism)<p>As an example, the author says that before agricultural revolution people had varied diet which was not possible afterwards, and that this was a price to pay. Maybe someone could say that as a result our digestive system improved/specialized a bit and it could not absorb nutrients better because of predictability in diet, etc. Would be interesting to know if such opinions exist and are valid.