Have you happened to try doing the Master Cleanse yet? I've never done a juice fast, but I do the MC often (anywhere from 10 to 21 days so far). The first time I did it a couple of years ago, I was able to break my addiction to CAFFEINE. And believe it or not, it was a bad addiction. It also really helped me get my other bad ("illegal") habits in check. My brother did it about a year ago and hasn't touched cocaine since...and he had a pretty bad habit, though I would hesitate to call it an addiction. Something about the cleansing properties really help the body to lose those cravings. And you feel fully energized and excited about change for the duration. Just a thought.

Good luck with your juice fast! I do intend to check that out sometime.