By this rhetoric, a lack of obesity and obesity-related illness in a population indicates that the population has consciously decided to be healthier, eat healthier, exercise more, and work less. In short, they are morally superior entities with stronger wills.

Since obesity and obesity-related illnesses spiked in America in the 1970s, and the rhetoric here implies that such illnesses are primarily about conscious choice and will, the conclusion is that humans in america before 1970 were stronger people- in will, mind, body. They were a more disciplined, moral people, who had the will to resist all unhealthy and processed foods, sleep properly, and work reasonable hours doing active labor.

I find that quite confusing, because I don't recall that ever being the case.