Answer: I will explain to him what a low-fibre diet and a high-fibre diet does. A diet high in fibre causes frequent bowel movement. So perhaps his bowel needs rest that's why his doctor told him to take a low fibre diet.
A low-fiber diet, is usually recommended during the flare-up periods of diverticulitis to decrease bowel volume so that the infection can heal. An intake of less than 10 grams of fiber per day is generally considered a low-residue diverticulitis diet.
