Dave B wrote: I'd love to see some studies that show positive benefits from cleanses, I certainly couldn't find any.
Why would such studies exist on the level of those done to meet FDA approval? Who funds such studies, and in who's commercial interest is it to counteract the prevailing science of the pharmo-industrial complex?
I, too became very interested in the topic and practices of cleansing years ago and had exactly the opposite experience of Dave B. The Gershon institute, for one keeps records of it's success (in terms of remission rates). Andrew Weil's website has links to many studies demonstrating the efficacy of various cleansing programs (which match my experience). Fasting is not an extreme measure--it's something our bodies are naturally adapted to do.
To the OP, do your own research, and you will find a lot of anecdotal evidence on both sides. A healthy skepticism is good--knee-jerk naysaying is not (I say to no-one in particular). My own anecdotal "evidence" is that a 3-day juice fast, while difficult, leaves me feeling rejunivated, energetic, and less inclined to crave "junk" (at least until my next road trip...).