People will get in shape ricky tick as you forbid them health insurance or fat tax them. Humans have no natural predator, no forced adaptations and selections - we must invent such.
Increasing sin taxes (alcohol and cigarettes) and raising insurance rates on those who choose to overindulge on those aren't effective so this wouldn't be either. Forbidding people health insurance because they're not "in shape" just feels wrong and a pathway to eugenics imo
And besides that, in countries where health insurance is to some extent or entirely public, you don't tend to see a rise in rates since health care is considered a kind of right.
You think people like being unable to control their body?
Yeah, right after we yank insurance for anyone who refuses to get vaccinated. Or is the heavy hand of authoritarianism (and the sneakier one of eugenics) only welcome when it falls on Other People?