I think it’s often a mental health issue. Rather than simply a physical one.
my sil is obese and has been most of her life, since mid twenties, she’s now late 50s. I on the other hand, was always a healthy weight then gained wirh menopause,
I went on the drugs as my health was suffering, high blood pressure, sleep apnea etc, she is also suffering health wise, but it’s more joint degradation, her knees, back, hips now getting surgical work, plus she’s arthritis and asthma all made worse due to her weight, but her bp is fine and no sleep apnea.
she hasn’t went on the meds, for her food is too much part of her life, she loves food, cooking, eating, shopping for it, and she loves snacking, etc and gets her dopamine from it, it’s a comfort, it’s a joy, but she’s catty to me about it, a bit envious and resentful that I am now slim and she’s still very obese.
I on the other hand was never that bothered by food, but due to increased cortisol with menopause, sleep apnea etc my portion size crept up and my insulin wasn’t working well.
clearly for her physical health it would be better for her to go on the drugs, but as much as she wants to be slim, for the aesthetics and she realises, her weight is causing much of her issues now, ultimately she wants the food more. It’s a life long habit she is unwilling to break. So for her mental health she feels it is not better for her to do this.
we also know on the drugs, unless you react badly or take too high a dose, then you can push through and still over eat. So if you do over eat due to pshycological issues rather than just physioLogical, then unless you’re in the right head space, you may struggle and find it harder.