One thing I've read/heard about with regards to using a drink to replace food is your body won't register as satisfied. When you aren't actively doing the mouth work on your fats, your body doesn't think you're consuming many calories. Cheetos are a super-engineered abuser of this: because so much of them dissolves before you chew them up and swallow them, the caloric density won't really register so you can just keep throwing them down without feeling it.
EDIT: Apparently there have been posts since page two.
Bad news for my Soylent anal douching gambit.