Consider Juice Feasting rather than fasting. The difference being in that on feasting you are doing greater amounts of juice where you are getting many more calories and some supplements are even recommended. Now this is no cart blanche for anything goes on supplements. The link below will take you to the online "Juice Feaster's Handbook" and it will all be explained there.
http://files.meetup.com/577895/A%20JuiceFeaster%27s%20Handbook.pdf
I'm on day 12 and loving it!! The whole concept makes total sense to me.
I guess it could be equated to some sorta pilgrimage cept without all the suffering, penants and Mea Culpa. Mine would be El Camino de Pepe and it would be in a self sufficient solar powered bus with a really nice music system, satellite comunications and an organic garden on top...................;+D
Cukes=cucumbers