You should really not be physically hungry - you can always drink more of the lemon drink. I don't go by the 6 - 10 glasses limit when I'm starting a Master-Cleanse because I'd rather stay on it and drink more than go off because I'm too hungry. One day I drank *15* glasses!!! But it all evens out, because later on in the Master-Cleanse I only drank 4 glasses one day.
Now, mental cravings are another thing entirely and more difficult to combat. You just have to stay busy and take your mind off food, easier said than done.