not OP, but I agree it is modern cultural problem and a personal responsibility problem.
However, I dont agree with your supposition following from that.
I think that obesity is a symptom of a cultural problem worth solving, not an individual moral failing, and there are better ways to learn than death.
There are lots of things in our culture that result in physical and mental sickness. It is good to treat the symptoms, but we should also pay attention to the cause.
Culture operates both at the individual and collective level. One can not exist without the other. One can not change without changing the other. Personal beliefs and actions shape collective culture, and culture shapes personal beliefs.