Hypnosis - for weight loss?

My FMIL gave me this tape that she got for weight loss. You're supposed to listen to it as you fall asleep and it makes you want to eat only healthy foods and small portions. Sounds a little too good to be true, but she used it a couple of years ago and lost about 20 pounds.

I'm going to listen to it tonight, but my question is, has anyone else tried something like this, and if so, did you see any results?