Taking drugs to lose weight might work well in the short term, but in the long run they will tend to kill your metabolism and make you fatter in the long run (just like anorexia, bulimia etc)
What you need to do is look at ways of speeding up your metabolism so you can keep the weight off! Have you heard anything about the ketogenic diet?
Humans today eat soooooo many carbs, (bread, pasta etc) and unless you are a serious athlete will never burn it all off. If you are consuming more fuel than you are able to burn, it gets stored as fat. Simple? It is!
Ketogenic diet involves eating lots of protein and very little carbs (fruit and vegetables only) plus lots of beneficial fats (nuts, fish, avocado -- these are ESSENTIAL to losing weight! Don't let them fool you!). Your daily meal plan might be: breakfast - scrambled eggs (no toast); lunch - salad and protein (like chicken or tuna); dinner - vegetables and protein (like meat or tofu). You can snack a fair bit, but it has to be protein snacks, I have boiled eggs and nuts and things.
This actually WORKS!!! Some doctors try to market this as an unhealthy, fad diet but it is basically a caveman diet, and that worked for about 100,000 years so how could it be wrong? Besides, you test your urine every day (you buy special test strips) to make sure you are producing the right amount of ketone bodies (a chemical produced by the body when fat is burnt).
The briliance with this diet? You only lose fat, not muscle, which makes it totally different to every other diet out there. The protein you eat increases lean muscle mass which means your metabolism gets faster, so you can burn off even more weight!!
By the way, I have studied this, not just read it off the internet or something. I have also used it on myself, and after years of losing weight by unhealthy means (bulimia, anorexia, drugs etc), I couldn't believe how easy this was. I did this a year ago and I'm still skinny now.
Good luck.
