In my opinion using adderall (amphetamine salts) as an intentional weight loss aid is not a good idea.
Combining amphetamines with exercise is a recipe for disaster. Amphetamine use can cause arrhythmia, increased blood pressure, and cardiomyopathy[1] by itself. Combining this with exercise, which will put a higher workload on the heart and raises blood pressure, can be potentially fatal. This is not to say that exercise and amphetamine use is going to kill you, that is very much a dose/ exercise intensity/ and frequency of use dependent equation.
There is definitely a trend with amphetamine use and complications relating to your heart. Not to mention, neurotransmitters and receptors are extremely complicated, they are not toys. Playing with them just to lose weight when self control can accomplish the same is idiotic.
Sorry to rant, its just lately a ton of topics about using amphetamines for weight loss and pre w/out have popped up and i find it frustrating, especially due to what my own experiences with them.
[1] Invalid Link Removed
Am J Ther. 2008 May-Jun;15(3):287-9.