jojo,
Not eating temporarily does not mean you are going to lose weight permanently. What happens, is your body will start to devour its own viable muscle/fats, but at a cost; lowering your metabolism.
When you don't eat for a significant amount of time, you will eventually eat again. At which point, you will be utilizing less of the food for energy. Meaning, if you thought you looked bad before...you'll probably look worse afterward.
If you don't believe me, try to find those anorexic chicks at your public schools when you were younger. If they were anorexic for long enough, they are probably fat now (ironic huh?).
The true key to losing weight lies below:
1) regular exercise (muscular and cardiovascular)
2) eating the right foods, and enough of it (but not too much)
3) not smoking cigarettes, not drinking alcohol, not regularly abusing drugs, not being addicted to drugs
4) changing bad habits into good ones (instead of eating junk food, eat fruits and veggies for fun, they give you a boost of energy too, obviously not as big of a boost of energy as amphetamines, but still...)
5) do not be sedentary! You need to be physically active. Look at #1, it is #1 for a reason.
Not one of these alone is enough for most people to make a drastic change in weight loss, tyipcally, you need to do most if not all of the 5 steps above.
Good luck!
PS don't go back to meth. You've come a long way in quitting. You don't want to risk being psychotic again. Just my 2 cents. Meth is best used once in a blue moon, not in binges.