Meth isn't an amphetamine, it's methamphetamine. Related, but not the same. Methamphetamine is actually stronger in terms of appetite suppression than amphetamines. Most amphetamine users regain their appetite (to a large degree, but usually not fully) after a few months of daily use, but I've never heard of anyone being able to eat on meth. And I live in Kentucky. So I've met quite a few meth heads...