We have guys here too.
I can't give you any feedback, not having ever tried a liquid fast for that long. I did read an article the other day that Doppelbock beer was created by monks who do a 40 day fast and "liquid bread" doesn't break the fast so they created a highly dense beer to get them through their fast. You can read about it
here. Not that I'm suggesting you try beer, just that it's been known to work. I had a co-worker that did this 3 month deal where all he consumed was a water/maple syrup/lemon concoction. He lost a tremendous amount of weight. I don't know if he kept it off, though. That would be my primary concern is what happens when you add back in solid food? You won't have developed good eating habits because you haven't been eating.