I don't think I could make it through even a day. I guess it's from inherited genes, but I have a really fast metabolism (I think that's the term, could be wrong. It's something like that), so no matter how much I eat, I get hungry within the hour and it's impossible for me to gain weight. I may gain two pounds from dinner, but all that is gone in an hour. So, I'm already underweight as it is and I'm not even on a diet. It really sucks. I'd probably end up in a hospital after a week with no food.
Well, maybe it's not that dramatic (the metabolism thing and needing constant food is true, though). Who knows? Maybe if I tried it, my body will surprise me, but I don't think so.
Oh, and just wanted to say that I admire all of you that can fast like that, because I could never ever do that. : P
Edit: I mean, I'm almost finished with dinner as I'm typing this, and I still feel hungry. So, yeah. I need my food.