Empirically, yes. Very few people who attempt to lose a substantial amount of weight via diet and exercise are able to lose the weight and keep it off over the long term. The latter part is the problem for most people.

Clearly it is in the US. I think it's a generational lack of understanding and poor habits. From my perspective each generation of an obese family seems to get bigger and bigger, and pass on those non-existent or bad habits to their kids. If your parents aren't modeling exercise and good behaviors the only avenue you have to learn from is school and that's easy to get left behind.

On top of that you're marketed with the shittiest food all day, your school probably serves food where only things like pizza and burgers are palatable.

It's all really a shame because exercise and eating well clear your mind and make you feel better. Even if you're a healthy weight eating shitty and sitting all day does things to your mental health.

Abstinence-only education always works!

I mean what percentage of the US is overweight these days, the number is scary high and it has a massive impact in productivity and Healthcare costs.