Has it been proven that hypnosis works for weight loss?

I have been takig diet pills to loose weight. I know the effects it has, but because of 3 different meds I am on that cause significan weight GAIN my doctor justified the pills. I have been off of them for 8 days and have gained back 5 lbs without overeating and still excercising extensively. I have a large appetite and tend to crave foods in the evening. I am a healthy person who does "all the right things" but just can't keep the weight off. I was hoping hypnosis might be the answer.