You’re basically blaming the drug for the person’s inability to psychologically deal with diet.
No, I don't. I'm just stating facts on how the human body works. With extreme willpower you might be able to counter this for a time, yes. But it will be a serious uphill battle, and the messenger chemicals from the depleted fat cells do not just stop because you will them to. You will just have to live in a state of perpetual raving hunger then. The few who can successfully overcome this for a significant time are rare, indeed.