The question at hand: “When does regulating a person’s habits in the name of good health become our moral and social duty?”
I dunno. I seem to recall from my history lessons that about 40 years or so ago, it was against the Rights of Man or something for people’s habits to be regulated by social peer pressure and public shaming, whether or not that behavior is a significant source of poor health and social pathology. If the sex drive can’t be regulated for the sake of keeping children out of poverty and all the associated social ills of ghetto lifestyles (including obesity), how is it now okay to talk about regulating what food people eat? At least gluttons aren’t going to be ruining other, innocent people’s lives by getting fat.
We’re already paying for all the bastard children and their “heroic” single mothers. Why not fork over money from the printing presses to cover the gluttons too? Why should the fornicators be paid for by society and not the gluttons? If we’re going to impose moral views on people, let’s impose the ones that will do the most good for the most vulnerable. Sluts ruin more lives than gluttons, after all.