Like 52% of the developed first world can be considered morbidly obese.
I highly doubt it's a willpower or self-control problem, that's just blaming the victim.
The real issue is there's fucking sugar in everything.
Read the nutrition facts labels one day and try to keep yourself under 100g of net carbohydrates as a mental experiment while grocery shopping (net meaning carbs - fiber = net).
You'll quickly notice that the vast majority of things have added sugar via HFCS, even innocuous things like bread or even ketchup.
It's tough out there.