Changing habits is hard, making choices is hard, doing things that feel uncomfortable is really hard. I have a lot of sympathy, for the idea and we all struggle with stuff like that.

But unfortunately this isn't a complicated subject. Weight is controlled by diet and standard healthy diets are very well known. Nearly everyone can keep their weight down. Even if people don't, it is objectively not that hard to do. A lot of people don't accept the rewards are worth the discomfort.