There's a lot of middle ground between body shaming and telling people with a BMI of 40+ that they are "fine the way they are", I think.

The same can be said about most western Europe countries, yet they still have obesity rates above 20% compared to 4% in Japan.

https://en.wikipedia.org/wiki/List_of_countries_by_obesity_r...

>But do go on about fat shaming being effective.

It looks like the most likely explanation here.

Why not? It works. Are you more concerned with someones feelings than their heart health? When they pass at a young age will their loved ones at their funeral think "wow, at least nobody ever hurt their feelings"?

The more people are exposed to weight bias and discrimination, the more likely they are to gain weight and become obese, even if they were thin to begin with. They’re also more likely to die from any cause, regardless of their body mass index (BMI).

Fat shaming is also linked to depression, anxiety, low self-esteem, eating disorders and exercise avoidance, Alberga said. There’s emerging evidence that the severity of harm increases when people internalize weight bias and turn it on themselves. In one study, participants with high levels of internalization of weight-bias had three times greater odds of having metabolic syndrome than those with low levels, even after controlling for BMI and other risk factors

There is also a huge difference between sharing candid concerns about someone's weight when you already know them and can be somewhat compassionate about it and shaming a random person you don't know.

Have you got some evidence for that because it sounds dubious to me.

[1] https://www.npr.org/2020/09/14/912029399/we-had-to-take-acti... (NPR: 'We Had To Take Action': States In Mexico Move To Ban Junk Food Sales To Minors)