Sorry, I didn't answer your other question! You do not have to fast when you do this cleanse. You will want to clean up what you eat, though.
For instance, cut out meat, bread, and milk and try to eat lots of fresh veggies. Don't worry, the psyllium sort-of stops you from getting hungry. But remember, you do not have to fast if that is a concern. I didn't.
If you have access to a juicer, that is great. Try to find one second hand if a new one is too expensive for you. (That is what I will be doing)