This is 100% because they fail to adhere to a caloric intake that is at or below their TDEE. That's about behavior, not physiology. They aren't violating the first law of thermodynamics and creating new mass and energy out of nothing. They're eating too much. They aren't tracking their weight and modifying their behavior when they see it going in a direction they and their physicians don't want.
It's no different than the fact that you must spend less than you make to avoid going into debt, and that you must save a certain percentage of your income to save up enough for retirement so that you can continue your standard of living once you retire. And yet we find huge portions of the US population in debt with little to no savings. This doesn't mean the advice is bad or invaluable.
This doesn't mean they're mentally incapable of saving up. That's a behavioral issue, too. And behaviors can be modified. There's research about how to successfully do that, too. Entire industries revolve around modifying behaviors to extract profit from people.
That the studies that you are personally aware of show that people have trouble maintaining a healthy weight suggests, not that it's impossible, but that the subjects don't know how to form and maintain habits.
That people can't implement advice doesn't mean it isn't valuable. At most, it just means they need more advice or counsel. But not different, mutually exclusive, advice.
It's no different than the fact that you must spend less than you make to avoid going into debt, and that you must save a certain percentage of your income to save up enough for retirement so that you can continue your standard of living once you retire. And yet we find huge portions of the US population in debt with little to no savings. This doesn't mean the advice is bad or invaluable.
This doesn't mean they're mentally incapable of saving up. That's a behavioral issue, too. And behaviors can be modified. There's research about how to successfully do that, too. Entire industries revolve around modifying behaviors to extract profit from people.
That the studies that you are personally aware of show that people have trouble maintaining a healthy weight suggests, not that it's impossible, but that the subjects don't know how to form and maintain habits.
That people can't implement advice doesn't mean it isn't valuable. At most, it just means they need more advice or counsel. But not different, mutually exclusive, advice.