1st, fiber free. With acute diverticulitis, rx involves antibiotics. Initial diet rx is with liquids only, allowing the inflammation to decrease. As inflammation decreases, diet is advanced to full liquids, low fiber solids (rice, plain pasta, potato, fish, chicken), then increasing fiber (cooked fruits and veggies first, progressing to fresh fruits and veggies, whole grains). Process usually takes about 7-10 days.