A drug that promotes weight loss, lessens the desire to smoke, drink, etc...sounds too good to be true? From what I have heard, all of these issues come back as soon as someone comes off the drug. So either a person is committing to a lifetime of being dependent on this drug, or a person is committing to some period of time of ideal living, followed by a possible time of depression after reverting to the status quo.
It does sound too good to be true. However, it's possible that the drug is working on all of these through the same mechanism: by altering the brain's reward system.
If that's true, the drug doesn't make you not want to eat, it makes you not want stuff, in general. That could potentially suppress a wide array of addictive behaviors. I also wonder if that suppression might look a lot like clinical depression, though.