In the new study, the Harvard Medical School team tracked over 367,000 healthy people who were taking part in the NIH-AARP Diet and Health Study, for an average of 14 years.
People who ate the highest amounts of whole grains had a 48% reduced risk of death from diabetes, and an 11% reduced risk of dying from respiratory diseases. And people who ate the most cereal fiber had 15% and 34% reduced risk of death from cancer and diabetes, respectively. In fact, when cereal fiber was removed from the equation, the associations disappeared almost completely, suggesting it was in fact the fiber itself that was mostly responsible for the health effects.
If you’re going to up your grain intake, make sure to choose whole ones, like steel cut oats, quinoa, or even whole grain bread, over refined ones like cereal flakes or white bread.
Top Fiber-Rich Foods
1. Bran
One simple way to increase fiber intake is to power up on bran.
| Food | Portion | Amount of Fiber |
| Oat bran, raw | 1 ounce | 12 g |
| Wheat bran, raw | 1 ounce | 12 g |
| Corn bran, raw | 1 ounce | 22 g |
| Rice bran, raw | 1 ounce | 6 g |
| Fiber One Bran Cereal | 1/2 cup | 14 g |
| All-Bran Cereal | 1/2 cup | 10 g |
| Fiber One Chewy Bars | 1 bar | 9 g |
2. Bean
They are one of the most naturally rich sources of fiber, as well as protein, lysine, vitamins, and minerals, in the plant kingdom.
| Food | Portion | Amount of Fiber |
| Lima beans, cooked | 1 cup | 14 g |
| Adzuki beans, cooked | 1 cup | 17 g |
| Broad beans (fava), cooked | 1 cup | 9 g |
| Black beans, cooked | 1 cup | 15 g |
| Garbanzo beans, cooked | 1 cup | 12 g |
| Lentils, cooked | 1 cup | 16 g |
| Cranberry beans, cooked | 1 cup | 16 g |
| Black turtle soup beans, cooked | 1 cup | 17 g |
| Kidney beans, cooked | 1 cup | 16 g |
| Navy beans, cooked | 1 cup | 19 g |
| White beans, small, cooked | 1 cup | 19 g |
| French beans, cooked | 1 cup | 17 g |
| Mung beans, cooked | 1 cup | 15 g |
| Yellow beans, cooked | 1 cup | 18 g |
| Pinto beans, cooked | 1 cup | 15 g |