This article will help to guide you regarding what to eat as you cope with the active attack and its aftermath. While your diverticulitis is active, your doctor will most likely recommend that you follow a liquid diet - no solid foods whatsoever - in order to help your colon rest and heal. Stick to the following: 1  Black coffee. 2  Broth.  Fruit juices (apple, pear, grape, cranberry, not orange) - no pulp.