Diverticulitis develops from diverticulosis, which causes pouches to form in the digestive tract. A low-fiber diet is the main cause of diverticular problems, as fiber helps reduce risks. While doctors once recommended avoiding seeds and nuts, there is no evidence they cause diverticulitis. A low-residue diet with less than 10g of fiber per day is recommended during flare-ups to allow healing, but a high-fiber diet can later help prevent future issues. The diverticulitis diet focuses on healthy eating with adequate fiber and fluids to support the body's nutrition needs.