Yeah just fucking diet and excersize. This may seem like a shock to you, I know, but I have actually seen people loose weight just by eating less or better and moving around a bit more.
If you're really looking to provide your body with what nature intended you should look into essential fatty acids. You can get these in the form of a fish oil capsule, hemp seed or hemp oil. Hemp provides omega-3 and omega-6 in the perfect ratio and hemp seed is also 33% protein.
Niacin (Vitamin B3) can be supplemented to promote energy, metabolism and nervous system health. This statement has not been evaluated by the FDA and niacin is not intended to diagnose, treat, cure or prevent any disease.