Patients undergoing a colonoscopy can eat broth, gelatin, water, ice pops and black tea before the procedure, as noted by Harvard Medical School. Nothing should be digested two hours before the procedure.
The patient's digestive system should be clear before having a colonoscopy done. A low-fiber diet should be followed a few days before the procedure. Patients should avoid any grains, nuts or dried fruits. The day before, only clear liquids should be consumed. Broths or bouillons can be eaten, along with any clear drinks, such as fruit juice. The doctor may prescribe a medication to be taken the day before to clear the bowels out before the colonoscopy is done.