So eating goes way down. Amphetamines also has the appearance of speeding up metabolic processes so it is hard to be still for very long. This dramatic, amphetamine-induced increase in activity also contributes to weight loss. Sorry, but it is not to be. There are numerous side effects to amphetamines, they are somewhat addictive, the desired effects wear off even as the body's dependence on the drug increases, and the lost weight always returns when one finally stops taking the drug.
Withdrawal symptoms can be serious and the lost pounds always come back with friends.
That is, you gain back more after you quit the drug than you lost while taking it. The problems associated with amphetamines are so serious the FDA in cooperation with the American Medical Association put strong restrictions on prescribing these drugs several years ago. Now they are primarily used for treating certain hyperactive children. If you go to your physician and ask for a prescription for amphetamines I can almost guarantee you will not get it. I've had experience with them, and they are bad news.