I would have to say that the lack of electrolytes definitely sounds like a large concern, but drinking a sports drink might be a little more reasonable than just plain salt water. Might even help you get through your homework too. I knew a guy who was on a liquid diet for months though, not just juice and water, but I mean, everything he ate seemed to be some form of liquid. The dude almost wasted away into nothing, he was like a walking skeleton. But a healthy person should easily be able to go one week without food. As far as a detoxification, I've heard that a lot too. Not a whole week, but even just going one day on water, or a weekend, is a good way to flush your body out and let your internals catch up on any waste processing. Kind of like changing your oil or something.