I have done lots of serious body cleansing over the past 7 years or so. Fasting will NEVER keep weight off, but is a good springboard for a sensible weight loss program of healthy eating and EXERCISE! The bottom line is, whatever you don't burn, you store. You do the math!
Have a great cleanse! Juices are definitely more supportive than the MC, but I would not say you don't tend to put weight back on with a vengeance after a juice fast, as you do with any fasting program. Again, the ticket is sensible eating and EXERCISE, particularly post-fast.