For the record, suppressing your appetite with stimulants doesn't slow your metabolism at all; it actually raises it a little because of its effects on your adrenergic receptors - there's more norepinephrine (noradrenaline) and epinephrine (adrenaline) effecting your system. While I do somewhat agree with the responses above, stimulants can, if used correctly, be a great tool to start dieting.
While others are saying that it is a bad idea, if done CORRECTLY, it could help to change your dieting habits. The key is that throughout the day, you have to keep reminding yourself to eat a LITTLE bit, and force yourself to do so. Optimally, to keep your metabolism up, you want to spread your eating out into about 9 sessions per day. Don't eat big meals (I would eat perhaps 3 very minimal meals (3-500 calories a piece, with your largest in the morning) and have 4-6 very light snacks (like 100 calories a piece)), and don't try to go on a binge for a few days not eating then go off, because while you probably won't make up the calories missed, you will probably gain most of your weight back from your body going into starvation mode.
I also used to use phentermine (was taking 75mg/day). I don't know if you're in Australia or where, but if you were on an extended release version of phentermine (and I don't know what dosages they Rx it in), but I was prescribed 2-37.5 mg tablets a day, but I would take them both in the morning, and it worked pretty well for the 4 months I was on it. I will say though, that when I went off of it, I gained back half the weight I had lost, but I can't stay active due to medical problems. That could have been a major factor.
Oddly though (and I don't advise you to do this at all lol), when I was on meth for a year (and there was some roller coaster effect on my weight) and was basically starving myself 4-5 days out of the week (involuntarily because with the amounts of meth I was doing, it burned my mouth and hurt my throat to eat), I went from 220 lbs. to 155 lbs. by the end. When I quit, I gained about 20 lbs back, but that was good because I didn't look like a scrawny stick, and I didn't gain back all my weight. It was a nice middle point. I stayed at that weight for half a year until I got injured, then got all the way back up to my high school freshman year weight of 260 and stayed there until I tried the phentermine.
I recently got my ADHD diagnosed and got prescribed Vyvanse. I plan on using it to optimize my eating habits (because I'm not exactly practicing what I preach in terms of how you should space out your meals at this point in time) when I get on the right dose, so that I might be able to get to a healthier weight.
I only use it because amphetamines are like unicorns where I live.
