transitioning from a juice fast

Hi,
I am oon day 13 of a juice fast. I am transitioning tomorrow on to The Master Cleanse as I am tired of juice and the work involved. I also need a change of taste. Has anyone ever done this? I would like to coplete a 4o day fast all in all, so I would do 27 days on the master cleanse. Does The Master Cleanse sustain you as well as the juice fast? Does anyone know? Thanks...Hanna