Hey, now. I think you already knew that whatever explanations for the
trend are out there wouldn't be happy ones.

I'm convinced that the solution, if there is one, will involve someone
coming up with a way to keep people healthy that is easier to
implement and makes significantly more money than the current
binge/purge cycle that makes money, so to speak, coming and going.

Any attempts to engineer it from a behavioral level will fail, as long
as people are exposed to advertising. Irresponsible people are easier
to exploit; no industry is EVER going to support encouraging people to
act responsibly.