The, uh, tone of your comment suggests that there is this epidemic of obese people who simply have neglected to press the STOP BEING OBESE button. "All you have to do is ..." "Can't you just ..." In technology, we hate hearing that from people who do not have a grasp of the situation -- why are you doing it here?
That button doesn't exist. That's the source of your bafflement.
You could same about "Can't you just take the jab?" and "Can't you just wear a mask?". If you want to be the one deciding who has to do something, then that's called authoritarianism and it's the reason why so many people are pissed off about the all of the covid restrictions.
That button doesn't exist. That's the source of your bafflement.