So obesity in America is a snowball effect and cannot be stopped.
Look at photographs from the sixties and seventies of Americans or even earlier. Normal people.
From the eighties onward they've become walking Bibendums. It's tragic if you think about it. An entire people incapable of eating healthy food. Children are obese, parents are obese. It's clear something went wrong between the seventies and the eighties. What ?
Marketing. I watched a show "The man who made us fat". Someone in a fast food chain (ok, I didn't pay a lot of attention...) worked out that if you gave out bigger portions and charged more, people still ate it all rather than leave it half-finished and 'waste it'.
Makes sense, if you think of it. When's the last time you just said "that's it, I've had enough" and didn't finish a meal that you'd paid for? (Especially a dessert...)