The Doctor should give you a complete list of what you can and cannot have prior to that day. For me it was chicken broth, orange Jello, black coffee (no cream or sugar) And I think apple juice was OK. The worse part is the DRANO Pills you have to take (to clean your pipes) and all the water you have to take with them. Lots and lots of water. Make sure you are home ALL day when you are doing this or you will mess your pants.
The best part is the day of the operation. You will never know it happened. And if you play up the “I'm still feeling groggy” line when you get home, you can be pampered by the wife the rest of the day.