Diet pills are just amphetamines they give you energy but as with all things there is a down side, you can't keep taking them and when you stop you'll get a massive downer. You are already doing the right thing eat sensibly and exercise. Gym uses calories but the real benefit is getting a fit body which will use more calories even when at rest. Also muscle uses more calories than fat. There is also the added benefit of increasing metabolism during and after exercise. Do not starve and your metabolism will do the job for you. It takes time be patient. Never take diet pills of any kind they cannot possibly work, you'll get mentally reliant on them and get no where. Good luck.