In my six year love affair with Meth, I have seen this many times over & it is saddening. I believe it comes from not only the side effects of the chemicals themselves, but also from not eating for great periods. You get very skinny very quick. I went from 268 to 155, in the course of almost a year ) my skin sank and my eyes looked hollow but to me my distorted thinking told me I looked damn good. When I would eat it would be very little or next to nothing. Another factor is how much you actually use and how long you take breaks for, because if you think about it, my binges would go on for a week and a half before I would eat a single thing, all the while being awake and tweaking, doing extreme amounts at one time. It sure does make a beautiful person turn into a hideous monster. I look back and cannot believe I was like that for a little over 6 years, it makes me sick. Thankfully I have since recovered and have gained some of that weight back. Ok..maybe more than a little but we aren't telling anyone.