I think its supposed to be a week, but that probably depends on how much fat you have stored on your body. I would eat at least something every night so that your metabolism doesnt raise in the morning and so that your body doesnt start metabolising/eating the muscles, bones, proteins, etc. in your body. Itll make your hair and skin look really shity, even mayb loose your hair, and youll get a huge pot belly. I REALL suggest you dont do this though. I suggest you go see your doctor or get out of whatever situation thats causing you to feel this way. You dont have to feel this way. Also, you wont want to take even a single bite of anything after a few days, andyou may get really sick from digestion or gas problems too, if theres nothng in your stomach to absorb the acid. Ive had that happen to me before. Please, not eating will just make it worse, believe it or not, youll just become more lethargic and apathetic.