Ok, I'm finally doing another juice fast... more info below. They really cleanse you out without dropping your metabolism (although you're generally getting a lot less cals) - you flush out tons of old crap, mucous and other stuff that just builds up in your system over the years. I'm going for 100 hrs. I'm 15 hrs in, 85 hrs to go.
More information on juice fasts (and breaking them without gaining weight back) is here:
http://www.healthy.net/scr/article.asp?ID=1996http://www.healthy.net/scr/article.asp?ID=1998http://www.freedomyou.com/http://www.fasting.com/problem.html They're super-cleansing, your whole body detoxes and flushes out all this crap that's been in your system forever, but you have plenty of energy b/c you are getting some calories.