Go for the 7 or 10 fast. You'll need to clean yourself out each day and you'll be amazed that there still will be matter coming out for many days into the fast. It's your body cleaning itself of unwanted material.
Hunger leaves the first day just drink water when you get the growlies and that will calm your stomach. Note the whites of your eyes when you complete the fast. They will be clear white like a childs eyes. I once completed a ten day fast and needed some things at my favorite health food store and when I walk in the women who owned the store said, "Here comes somebody who just came off a fast". How'd you know that, said I? She said she could tell by the whites of my eyes.
Remember to come off the fast S..L...O...W...L...Y...