I know how you feel, I often go n crazy diets to lose weight fast. First let me say that the slower the weight comes off the longer it stays off.. it's a fact. But there are times when slow won't work so I reccomend diets like the Rotation Diet (you eat 600 cal for three days, 900 for 4 days and then 1200 for a week and then repeat the 600/900 week, then take a week off and then begin again) you should lose about 2/3 a lb a day if not more. But you have to exercise too! Or there's the scarsdale medical diet (
http://lowcarblisa.tripod.com/thescarsdalemedicaldiet/ ) People lose fast on it. But remember one thing... when you lose really fast you have to work extra hard to maintain or you will gain everything back in record time, and don't forget to exercise or you'll slow your metabolism down and when you do try to maintain you won't be able to eat much at all without gaining. So just be careful and listen to your body.