You need to read this site on Lemonade Diet and Fasting to Lose Weight (with quotes from 17 MDs). It explains that distilled water is best. It also has a page explaining all about water and why you should never drink regular water but distilled or purified water (not filtered).
It explains how metabolism is not screwed up, but adjusts to your needs. The fatter someone is, the less it slows down. Either way when you start eating it speeds up. It is like a car. Cars can go at any speed as needed not just one speed.
Only a prophet can predict how much you will lose. The body does what it feels is best. Lose weight and your clothes will be loose. Cleansing symptoms can be awful but, and this is a big butt, the worse they are, the more desperately you needed the fast for your health. When people want to know how you lost weight, tell them the quote (on site above) about using it to lose weight by the New England Journal of Medicine.