Fiber 101
By Sarah Laswell
What is fiber?
Fiber is a form of a carbohydrate that can’t be digested that usually stem from
plant-based foods. 1,2 There are two types of fiber. Soluble fiber comes from fruits and
vegetables and helps keep you full as well as maintain cholesterol and blood sugar
levels. 1 Whole grain products are high in insoluble fiber, which helps prevent
constipation. 1 Although most fiber-containing sources have a combination of soluble and
insoluble fiber. 1,2
You might wonder, “Well if I can’t digest it, then why do I need it?” Well fiber has
numerous benefits; I list some of these benefits out below.
Benefits of fiber:
- It regulates appetite and helps keep you full longer. 1
- It may reduce the risk of cardiovascular disease. There is an associated lower
mortality risk from cardiovascular disease with a higher fiber intake. 1,2 - It reduces the risk of colorectal cancer, which is third leading cause of cancer.
Therefore, eating enough fiber may help protect you against it. 1 - It improves gut motility, which is just a fancy term for saying it helps you go to the
bathroom and prevents constipation. 1 - It may help improve insulin resistance, improve insulin sensitivity, and lower
hemoglobin A1C. 1 - It improves your gut-microflora, likely by protecting your intestinal barrier and
improving the overall health of your colon. 1 Along with that, prebiotic fiber is a
certain type of fiber that feeds the “good bacteria” in your gut. 2 - It may help lower inflammation in the colon and throughout your entire body.
Reducing overall inflammation may reduce the risk of or improve depressive
symptoms. 1 - Soluble fiber can reduce lipoprotein and total cholesterol levels by increasing the
rate that bile acid is excreted. 2
How much do you need:
The Dietary Guidelines for Americans recommends receiving 14 g of fiber for
every 1,000 calories you eat. 3 Based on their age and sex estimated needs, this comes
out to be:
Males
Age (years) Recommended Fiber Intake (grams) 3
2-3 14
4-8 20
9-13 25
14-18 31
19-30 34
31-50 31
51+ 28
Females
Age (years) Recommended Fiber Intake (grams) 3
2-3 14
4-8 17
9-13 22
14-18 25
19-30 28
31-50 25
51+ 22
High fiber sources: 4
Grains
- Ready-to-eat, high fiber cereals
- Popcorn
- Bulgar
- Spelt
- Teff
Fruit:
- Raspberries
- Loganberries
- Blackberries
- Asian pears
- Blueberries
Nuts/Seeds:
- Pumpkin seeds
- Chia seeds
- Almonds
- Chestnuts
- Sunflower seeds
- Vegetables:
- White lima beans
- Artichoke
- Navy beans
- Small white beans
- Yellow beans
Tips while increasing your fiber:
- Increase fiber slowly. If you increase fiber too fast, it may cause bloating,
constipation, or other gastrointestinal issues. - Drink more water. Drinking more water as you increase your fiber helps make
sure that your stool stays soft and prevents you from becoming constipated. - Monitor digestion and bloating. If you feel bloating or abdominal discomfort, try
decreasing fiber temporarily and then slowly increasing fiber again after a week
or two has passed. - Monitor blood glucose levels if you have diabetes or insulin resistance to make
sure that you know how your body is responding to the additional fiber.
References
- Barber TM, Kabisch S, Pfeiffer AFH, Weickert MO. The Health Benefits of Dietary
Fibre. Nutrients. 2020;12(10):3209. Published 2020 Oct 21.
doi:10.3390/nu12103209 - Surampudi P, Enkhmaa B, Anuurad E, Berglund L. Lipid Lowering with Soluble
Dietary Fiber. Curr Atheroscler Rep. 2016;18(12):75. doi:10.1007/s11883-016-
0624-z - US Department of Agriculture and US Department of Health and Human
Services. Dietary Guidelines for Americans, 2020-2025. 9th ed. 2020.
https://www.dietaryguidelines.gov/sites/default/files/2021-
03/Dietary_Guidelines_for_Americans-2020-2025.pdf - US Department of Agriculture and US Department of Health and Human
Services. Food Sources of Dietary Fiber. In: Dietary Guidelines for Americans,
2020-2025. https://www.dietaryguidelines.gov/resources/2020-2025-dietary-
guidelines-online-materials/food-sources-select-nutrients/food-sources-fiber
