In the past, people with small pouches in the lining of the colon (diverticula) were told to avoid nuts, seeds and popcorn. It was thought that these foods could lodge in diverticula and cause inflammation (diverticulitis).But there's no evidence that these foods cause diverticulitis.If you're trying to prevent diverticulitis attacks, focus on eating an overall healthy diet that's high in fiber. High-fiber foods, such as fruits, vegetables and whole grains, soften waste and help it pass more quickly through your colon.ut there's no evidence that these foods cause diverticulitis. If you're trying to prevent diverticulitis attacks, focus on eating an overall healthy diet that's high in fiber. High-fiber foods, such as fruits, vegetables and whole grains, soften waste and help it pass more quickly through your colon.