That's true for an individual, but if you're looking at a population then you're seeing a situation where we have zero other solutions that are actually effective at curbing obesity. The only "natural" way to solve it is probably to overhaul our entire culture, redesign our cities and neighborhoods, et c., and that's not happening.
Skinny people move to the US and get fat. They're not skinnier back in their home country because they've got greater willpower or are harder workers, but because they aren't in the US. If harder work isn't why skinnier countries are skinnier, we shouldn't expect it to help us out of our problem, and indeed, we have nothing else we've studied that is terribly effective over time, and certainly nothing cheap enough to deploy on a large scale.
Again, yes, for an individual your perspective is the only thing one has (well... until these drugs) but looking from a policy level, it's useless.
A person's body mass is nothing more than the combination of what a person eats and what a person does in their life.
The only really effective policy is to inform people that that is the simple, honest truth of every single person, and that the quality of food we eat is important in that equation.
Eat better food, be more active. Yes, it is difficult, especially for us peasants.
But that is science. I hope a miracle drug helps folks preyed upon by the food industry, but side effects of that industry's drugs leave me skeptical of their being lastingly beneficial.