Good name, Somebodycallvogue :). I approve of this name. [nods wisely]

This is kind of impossible by definition:

water fast = only water, no supplements, no tea, etc. So by definition, the moment you take supplements, you are no longer water-fasting.

The moment you decide to incorporate supplements, juices, etc (which is what you will need to do to replenish vitamin/mineral reserves), what you are doing is a modified fast.

Given the amount of weight you want to tackle with fasting, you are probably looking at a modified fast or a series of Water Fasts anyway. I am not raining on your parade, please don't get me wrong - I think it's admirable to be motivated by a big goal that excites you - but no matter your starting weight, once you pass day 20 if you stay on pure water it's a matter of time until you get short on electrolytes, vitamins, and minerals. Being short on electrolytes, vitamins, and minerals is no joke. It can kill you, *even if you still have fat on you to feed you.*

So, realistically, you are looking at some mixture of juicing, intermittent fasting, or Water Fasts interspersed with refeeding periods of around a month where you eat clean, eat your veggies and good fats, eat a maintenance amount of calories each day, and supplement. You want to fast off 120 pounds? We'll support you. Hell, I want to fast off 75 pounds. But do your research, and do it safe -- by which I don't mean mainstream-media safe, where the health advice people give has to be the blandest possible so they don't get in legal trouble, I mean that there are some actual, very dangerous, potentially lethal or long-term damaging things that can happen to you. Do solid research to know what's possible.