Disclaimer: I've never used appetite suppressants, or been overweight but here are a few tricks of the trade.
If you are always snacking, try chewing sugar-free gum.
Drink some herbal tea, or water, or diet soda when you get the itch.
Plan your meals for the day, write it down, and stick to the plan. If it isn't on the plan, it doesn't go in your mouth. Really. You can do anything for one day. Then just do it again the next day.
NUMBER ONE TRICK - Let your body get used to feeling a little bit hungry. The eating is a habit you can break. Seriously, it beats being fat or dead.
Good luck. There are plenty of people on here who were once heavy and are now looking hot.