Which Foods Are High in Insoluble Fiber?

Medically Reviewed on 9/9/2021
insoluble fiber
Foods high in insoluble fiber include fruits, nuts and seeds, vegetables, wheat bran and whole grains.

Insoluble fiber does not dissolve in water, does not form gels (is not viscous) and is more difficult to digest. As such, this type of fiber, including cellulose, contributes to the formation of structures such as the outer layers of whole grains (bran), celery strings, seed hulls and corn kernel skins.

Even after hours of cooking, insoluble fiber retains its shape and rough texture, which effectively helps the digestive system by adding bulk to stools and easing their elimination. The main components of insoluble fiber and resistant starch are cellulose, hemicellulose and lignin.

Insoluble fiber can be obtained from various sources including the following:

  • Fruits
  • Nuts and seeds
  • Vegetables
  • Wheat bran
  • Whole grain foods
Table. Foods high in insoluble fiber
Food item Serving size Insoluble fiber (g)
Artichoke, cooked 1 medium 1.8
Brussel sprouts, cooked 1 cup 1.9
Carrots, raw 1 medium 1.5
Kale, cooked 1 cup 5.1
Lima beans, cooked 1/2 cup 2.2
Potato with skin 1 medium 2.4
Soybeans (edamame) 1/2 cup 2.2
Sweet potato, peeled 1 medium 2.2
Apple, red, fresh with skin 1 small 1.8
Apricots, fresh with skin 4 1.7
Blueberries, fresh 3/4 cup 1.1
Figs, dried 1 cup 1.6
Kiwifruit, fresh 1 large 1.0
Mango, fresh 1/2 small 1.2
Pear, fresh 1/2 large 1.8
Raspberries, fresh 1 cup 2.4
Strawberries, fresh 1 3/4 cup 1.7
Whole Grains
Barley, cooked 1/2 cup 0.9
Brown rice, cooked 1/2 cup 0.1
Oat bran, cooked 3/4 cup 1.8
Oatmeal, dry 1/3 cup 1.3
Oatmeal, cooked 1 cup 1.6
Quinoa (seeds), dry 1/4 cup 3.8
Quinoa, cooked 1/2 cup 2.5
Wheat bran 1/2 cup 1.0
Wholegrain pasta, cooked 1 cup 2.2
Nuts, Beans & Seeds
Almonds, raw 1 oz 3.5
Black beans, cooked 1/2 cup 3.1
Flaxseeds 2 tbsp. 2.1
Garbanzo beans, cooked 1/2 cup 2.8
Kidney beans, cooked 1/2 cup 2.9
Lentils, cooked 1/2 cup 3.8
Psyllium seed husks 2 tbsp. 0.9
Sesame seeds 1/4 cup 2.6
Split peas, cooked 1/2 cup 2.4
Sunflower seeds 1/4 cup 1.9
Walnuts 1 oz 2.5

What are the benefits of including foods rich in insoluble fiber in my diet?

Whereas soluble fiber dissolves in water, insoluble fiber does not and is not completely broken down by colonic bacteria. It instead retains water, promoting a larger, bulkier and more regular bowel movement. This, in turn, may be beneficial in the prevention of intestinal disorders such as diverticulosis and hemorrhoids, since it may help good bacteria in the gut.

  • Insoluble fiber has numerous benefits for intestinal health, including lowering your risk of constipation and preventing infection in the gut.
  • It removes toxins and carcinogens that cause cancer and helps prevent colon cancer by maintaining a healthy pH in the intestines.
  • It aids in weight loss and, to a certain extent, prevents heart disease and inflammation.

Insoluble fiber is sometimes referred to as a bulking agent because it aids in digestion while delivering health benefits such as lowering serum cholesterol levels. This type of fiber does not include any calories and usually has little nutritional value because it cannot be digested immediately. It contributes bulk as semi-digested foods pass through the body as a non-digestible substance. As a result, insoluble fiber is extremely beneficial to the human body. Consuming insoluble fiber in reasonable amounts poses very few risks as an essential component of the human diet.

What are the possible disadvantages of insoluble fiber?

Insoluble fiber has the disadvantage of irritating the walls of your colon. Raw vegetables are not recommended if you have irritable bowel syndrome (IBS), Crohn's disease or any other condition that causes your colon wall to be sensitive. Insoluble fiber is beneficial to the body, but too much of anything causes reactions, albeit mild.

Excessive insoluble fiber consumption causes health problems such as:

People with certain digestive conditions, such as IBS and ulcerative colitis, are usually advised to avoid insoluble fiber because it can aggravate their symptoms. Your body will need time to adjust to your increased insoluble fiber intake, so add more insoluble fiber to your diet gradually and drink plenty of water while doing so.


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Medically Reviewed on 9/9/2021
Dietary Fiber: https://badgut.org/information-centre/health-nutrition/dietary-fibre/

Fiber Facts: https://sci.washington.edu/info/forums/reports/FiberFacts.pdf

Soluble Fiber vs. Insoluble Fiber: https://uccs.edu/Documents/healthcircle/pnc/health-topics/Soluble_Insoluble_Fiber.pdf