I've heard from several people that if you don't eat your body will slow its metabolism and store fat and burn carbs and protein causing you to lose muscle mass. So if the meds make you lose your apettite and not eat would your metabolism slow because of the fact that your body isn't getting food?

I haven't heard this specifically in relation to ADD meds, but what you said is true in general. If you don't eat, your body thinks you're starving and starts burning less fuel. It's important to not stop eating on medication -- hopefully it might make it easier to be more temperate if that's been a problem, but not eating isn't healthy and won't keep the weight off in the long run.

Scattered