Aversion therapy is popular amongst hypnotherapists and some psychologists. The results can be questionable, but there is no doubt that for some people aversion therapy is effective. So it is worth exploring, but only as part of the bigger picture. If aversion therapy is the only thing you do, the results are likely to be disappointing.
So what is aversion therapy? Well, it is creating a negative feeling/response to a thing that previously was highly attractive and/or desirable.
For example, dog trainers may use a tin can will some stones in it to rattle loudly when the dog does something that it is being trained not to do. The dog reacts negatively to the stimulus of the unpleasant noise, and quickly pairs this response to the behaviour.
Punishing children is a form of aversion creation. The child learns that when he draws on the bedroom walls he gets punished. In order to avoid punishment, he avoids drawing on the bedroom walls.
Hypnotherapists may create aversion by getting the person to think of the thing they over-eat or crave, say chocolate, and then suggesting contaminating the thought with something noxious. The noxious suggestion might be an unpleasant food, hair from the plughole, or something else nasty. You can try this yourself.
Another technique is to use noxious smells. Whilst you chew the chocolate, you sniff something nasty and unpleasant. The brain begins to pair the chocolate with the nasty smell.
Another technique that has been tried for decades in aversion training is to wear a loose elastic band around the wrist. When you think about the chocolate, you snap the elastic band on your wrist. The chances are that within a few days you will start to get a very sore wrist indeed.
The results are not always immediate and some persistence may be needed, and the result varies. But aversion is worth considering.