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.
"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.