Fiber Tip Sheet

Fiber plays an important part in helping maintain good gut health and although it isn’t a nutrient, fiber is recognized by most physicians and scientists as vital to everyone’s diet – increasing bulk in our diet without adding calories. Increasing or maintaining dietary fiber should be part of a lifelong pattern.

What is fiber?

Think of fiber as the tough parts of plants; the stalks and stems. When we eat fiber, our stomach and small intestine can’t fully breakdown it because it is too tough. When it finally reaches the lower intestines, good bacteria can start to break it down. Fiber is very important part of our diet. It helps aid in digestion, keeps things moving and prevents constipation. 

Where is fiber found?

Fiber is found in only plant foods such as fruits, vegetables, beans and greens. Plants foods contain different kinds and amounts of fiber. Two different kinds of fiber exist; soluble and insoluble. Soluble fiber dissolves in water to form a gel-like substance. Examples are oats, beans, carrots, citrus fruits and psyllium husk. Insoluble fiber increases stool bulk and examples include beans, whole wheat flour, nuts, wheat bran and veggies such as cauliflower and potatoes. A variety of soluble and insoluble foods is the best option to maintain regularity. If you are 50 or younger, men should aim for 38 grams of fiber and women should aim for 25 grams of fiber daily. If you are 51 or older, men should aim for 30 grams of fiber and women should aim for 21 grams of fiber daily. Whole grains, fruits, vegetables, beans, legumes and nuts and seeds are the best options.

What can fiber do for health?

There are many benefits of having fiber in your diet! Fiber increases the size and weight of your stool, making it easier to poop. This helps reduce the chances of constipation because a bulkier stool moves more smoothly through your intestines. If you’re experiencing loose or watery stools, fiber can help by absorbing excess water and adding bulk, which can make your stool more solid and easier to manage. Fiber can also lower your risk of developing colon cancer, hemorrhoids and diverticulitis. High fiber foods are also usually more filling so it helps in maintain a healthy weight, stay full longer and eat less. 

How does fiber work?

Fiber is often called “nature’s broom” because it helps sweep away waste from digestion and keep things moving smoothly in our bodies. It soaks up water, making food bigger as it travels through our intestines. This extra bulk stimulates the muscles in our intestines, helping waste move along and be pushed out regularly. This regularity reduces strain on our blood vessels and lower bowel, keeping everything healthy and comfortable.

What is the recommended way to improve daily fiber intake?

If your diet isn’t high in fiber already, you should gradually increase high fiber foods and stay hydrated to avoid constipation, abdominal cramping and abdominal bloating. 

Fruits- Fruits with edible skin and/or seeds are highest in fiber.  To get the most fiber, eat apples and pears with skin, oranges and grapefruit sections and berries.

  • Vegetables: As with fruits, vegetables with edible skin or seeds are highest in fiber. Raw or crisp-cooked vegetables are the best.  Some high fiber vegetables include broccoli, peas, acorn squash and potatoes with skin.
  • Bread and Cereals: Bran cereals, whole grain breads, brown rice, bulgur, barley and whole grain crackers
  •  Beans and Legumes: Beans and legumes such as baked beans, navy beans, pinto beans, lima beans, soybeans, dried peas and lentils.
  • Snacks: Nuts, seeds, low fat popcorn and dried fruits. 
  • A fiber supplement, like Metamucil, is also another option. 
  • Making small switches in food can also add more fiber in your diet. For example: using whole grain rice instead of white rice or adding beans to soups or stews. 
FruitsServing size (grams)Total fiber (grams)*
Raspberries1 cup (123)8.0
Pear1 medium (178)5.5
Apple, with skin1 medium (182)4.5
Banana1 medium (118)3.0
Orange1 medium (140)3.0
Strawberries1 cup (144)3.0
VegetablesServing size (grams)Total fiber (grams)*
Green peas, boiled1 cup (160)9.0
Broccoli, boiled1 cup chopped (156)5.0
Turnip greens, boiled1 cup (144)5.0
Brussels sprouts, boiled1 cup (156)4.5
Potato, with skin, baked1 medium (173)4.0
Sweet corn, boiled1 cup (157)4.0
Cauliflower, raw1 cup chopped (107)2.0
Carrot, raw1 medium (61)1.5
GrainsServing size (grams)Total fiber (grams)*
Spaghetti, whole-wheat, cooked1 cup (151)6.0
Barley, pearled, cooked1 cup (157)6.0
Bran flakes3/4 cup (30)5.5
Quinoa, cooked1 cup (185)5.0
Oat bran muffin1 medium (113)5.0
Oatmeal, instant, cooked1 cup (234)4.0
Popcorn, air-popped3 cups (24)3.5
Brown rice, cooked1 cup (195)3.5
Bread, whole-wheat1 slice (32)2.0
Bread, rye1 slice (32)2.0
Legumes, nuts and seedsServing size (grams)Total fiber (grams)*
Split peas, boiled1 cup (196)16.0
Lentils, boiled1 cup (198)15.5
Black beans, boiled1 cup (172)15.0
Cannellini, Navy, Great Northern beans, canned1 cup (180)13
Chia seeds1 ounce (28.35)10.0
Almonds1 ounce, about 23 nuts (28.35)3.5
Pistachios1 ounce, about 49 nuts (28.35)3.0
Sunflower kernels1/4 cup (32)3.0

References
Mayo Clinic. 2022. Dietary Fiber: Essential for a Healthy Diet. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/fiber/art-20043983
Mayo Clinic. 2023. Chart of High Fiber Foods. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/high-fiber-foods/art-20050948