At a startup camp weekend, I've made this (incredibly sketchy, amateurish) app (NSFW) which implements classical conditioning to create a negative response to candy, smoking, or meat.
After using it intensively for about a day while writing it, I certainly feel disgusted at the sight of candy or chocolate. There's a little bit of evidence that something like this could actually have an effect on people: I'm reminded of the penny jar fetish experiment and this chapter on "curing" homosexuality.
I post this here for two reasons: to get advice on how to improve the app, and to get your opinions on whether this type of program might actually be useful. I'm reminded a bit of Anki, how the science led to the effective app. In this case, I'm not sure if it will turn out to be actually useful: in the experiments which have shown an effect from aversion type stimulus like this, the unpleasant image has been causally connected to the stimulus we're conditioning against, eg unhealthy food and diseased tissue.
Go easy on the web design, I'm just an amateur. :)
Thanks
EDIT: Yeah, it should be marked NSFW. Sorry.
I did this to myself as a kid. It was amazingly easy and strong. Downside was that being in the presence of the food also became nauseating (based on odor not sight). It also leached weakly into foods with similar smells. It started to diminish after about 10 years and was mostly gone in 20.
I think I once had some spoiled chocolate milk, but I don't remember getting sick from it and don't know if that had anything to do with why I don't like many forms of chocolate. (In particular, I can't stand chocolate milk, chocolate ice cream, chocolate cake, and Hershey's Kisses.)