nomad girl
I've done juice fasts where I continued to smoke. I usually find as I get more into the fast, and start feeling more and more healthy, I no longer want a cigarrette.
The desire just drops away. You will still have results from the fast if you smoke but obviously you are putting more toxins in your body as you are flushing them out.
Don't try to fight it, just observe how healthy you feel and your cravings for a smoke, and the desirve may just drop away on it's own... at least it works for me!
It IS a great way to quit if you can. Good luck!