What interests me is how anybody could ever come to believe otherwise. The contrary belief flies in the face of all common sense, popular experience and medical science. It seems to come entirely from propaganda on social media telling fat people what they want to believe.
I think there are several reasons: 1. Historically being fat was considered a sign of good health. Of course, this was during times of massive food scarcity and the definition of fat was probably very different from what we consider fat today. 2. Massive amounts of money involved in telling people to eat/drink more, and then spend more money in gyms and taking pills to lose that weight. As opposed to just eating less…
I think it's better to stick to that, and just drop the term 'fat-shaming'.