 [ Symptoms ] what am i allowed to eat before having a colonoscopy [ Disease ] nothing at least not after midnight the night before and do not drink anything either a few bites of food or sips of coffee before your colonoscopy may seem like no big deal but you will not be fooling your gastroenterologist a little food goes a long way toward obscuring the view of your colon that makes it harder to identify any polyps or potential tumors during a colonoscopy it might seem almost unbearable to go hungry or face a medical procedure caffeine free but think how much more uncomfortable it will be to undergo a repeat colonoscopy because of your “poor prep ” peanut butter