The below is from the Day 7 instructions from the 21 Day Cleanse…
“In the Second Week of this Program we will be eating lighter, with more fluids, culminating in a one-day water fast on Thursday. The water fasting day in the middle of two liquid-only days will totally rest our organs so that they can come back functioning at their very best! This kind of rest will lower your stress levels to the point that your chemistry will actually change allowing you to lose weight more easily, especially around your middle.
We’ll take three days to ease in to the water fast, and three days to ease out of it, so it will be very gentle.
It might sound scary to think of just drinking water for a whole day, but I find it much easier than any other type of cleanse. Maybe because I’m an extremist, it is somehow easier for me to stick to something that really feels hugely different and amazing from the outset. Or maybe because I don’t have to think about food at all, so none of my issues come up. I hope you’ll treat yourself to this wonderful fast, embracing the adventure – You will be amazed at the beautiful thoughts and feelings that will be yours throughout the day!
– from 21 Day Cleanse