My point is, unless you have found a way to break thermodynamics, the only way to reduce your weight is by taking in less than what you excrete out, regardless of deficiencies and conditions.
Sure. But we know that some conditions, both physical and psychological, can make that process much harder. (Medications, too! And billion dollar companies who employ experts in breaking your will.)
"Just abstain" approaches have failed repeatedly and conclusively in public health. Hell, it's hard enough to get people to wash their hands after pooping and get vaccinated.
Personal experience: the first time i took buproprion/naltrexone it became clear to me why people that arent and have never been overweight think "just eat less move more" is the only advice you need.
Except it's not typically very effectively actionable advice.
It's more in the realm of "just be happy" to a depressed person. Sure, that'd help a lot. It's the how that's tough. So we move the levers that aren't rusted solid first.
There are no fat children in those places in Africa where they go hungry. And I guarantee you a lot of people have conditions and imbalances there.