High-Fiber Diet
Eating a diet high in fiber can have many health benefits and might even lower your risk of colorectal cancer. Find out more about the benefits of a high-fiber diet and how to add more fiber to your diet.
What is dietary fiber?
Dietary fiber (often just called fiber) is the part of foods that we can't digest. Fiber is found in many plant foods, including beans, peas, lentils, whole grains, fruits, vegetables, nuts, and seeds.
What is soluble and insoluble fiber?
Dietary fiber can be either soluble or insoluble.
Soluble fiber attracts water into the intestines and becomes a gel. It can help lower blood sugar and cholesterol levels. Foods higher in soluble fiber include:
- Whole fruits like apples, bananas, citrus fruits, and berries
- Vegetables like beans, peas, carrots, and sweet potatoes
- Oats and oat bran
Insoluble fiber doesn’t dissolve in the stomach. It helps move food through your digestive system and adds bulk to your stools to help prevent constipation. Foods higher in insoluble fiber include:
- Nuts and seeds
- Vegetables like leafy greens, broccoli, cabbage, carrots, green beans, lentils, and celery
- Whole grains like whole wheat and brown rice
Many vegetables and whole grains contain both types of fiber.
What is a high-fiber diet?
A high-fiber diet includes foods with at least the recommended daily amount of fiber. This includes both soluble and insoluble fiber.
The recommended daily fiber amount depends on your age and sex. It can vary from 20-35 grams per day. A good goal for most people is to try to eat at least 28 grams each day.
Benefits of a high-fiber diet
Eating a high-fiber diet can provide many health benefits. It has been shown to:
- Prevent and relieve constipation and some types of chronic diarrhea
- Decrease your risk of heart disease and stroke.
- Lower your risk for and help manage type 2 diabetes.
- Help you reach and stay at a healthy body weight.
- Decrease your risk of cancer, especially colorectal cancer.
A high-fiber diet also might decrease your risk of the other types of cancer that are linked to excess body weight, such as breast (after menopause), endometrial, esophageal, gallbladder, kidney, liver, ovarian, pancreas, stomach, thyroid, multiple myelomas, and meningioma.
If you have cancer and don’t have any problems eating during and after treatment, you might want to try a high-fiber diet to stay as healthy as possible. This diet might also help lower your risk of getting a new cancer.
Starting a high-fiber diet
It is best to add more fiber to your diet slowly. Adding too much fiber too quickly can cause gas and other intestinal distress. Gradually add a few grams of fiber to your diet over time until you reach your goal.
Here are high-fiber foods you can eat if you’re following a high-fiber diet or want to increase fiber in your diet.
Protein: beans, seeds, and lentils
- All beans, peas, and lentils
- Nuts
Vegetables and potatoes
- All raw or steamed vegetables
- All types of beans
- Potatoes with skin
- Peas
- Corn
- Cabbage, broccoli, cauliflower, Brussels sprouts, and greens
- Sauerkraut
- Onions
Fruits and desserts
- All raw or dried fruits
- Berries
- Prune juice, prunes, and raisins
Breads, cereals, and grains
- Brown or wild rice
- Whole grains, cracked grains, or whole wheat products
- Kasha (buckwheat)
- Cornbread or cornmeal
- Graham crackers
- Wheat bran or germ
- Nuts
- Granola
- Coconut
- Dried fruit
- Seeds
Other high-fiber foods
- Marmalade
- Pickles, olives, relish, and horseradish
- Popcorn
- Potato chips
Tips for being on a high-fiber diet
It is best to get fiber from your food instead of supplements. Supplements have not been shown to have the same benefits for preventing disease as fiber from food.
If you need or choose to be on a high-fiber diet, follow these tips to keep your digestive system working its best:
- Drink plenty of fluids
- Get regular physical activity
- Eat smaller meals more often so your digestive system doesn’t have to work as hard
Ask your cancer care team if there is any reason you shouldn’t follow a high fiber diet. If you have questions about this diet, talk with your cancer care team or ask to be referred to a registered dietitian.
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- References
Developed by the P站视频 medical and editorial content team with medical review and contribution by the American Society of Clinical Oncology (ASCO).
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World Cancer Research Fund. Fibre, Wholegrains and Cancer. Accessed at https://www.wcrf.org/preventing-cancer/topics/fibre-wholegrains-and-cancer/#what-are-the-links-between-fibre-wholegrains-and-cancer on December 12, 2025.
Last Revised: December 22, 2025
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