peas ), bran (17 grams per cup), prunes (12 grams), Asian pear (10 grams each, 3.6% by weight), and quinoa (9 grams). [ 6 ] Rubus fruits such as raspberry (8 grams of fiber per serving) and blackberry (7.4 grams of fiber per serving) are exceptional sources of fiber. [ 7 ] [ edit ] Fiber supplements