Dietary Fiber
Also known as Fiber, Total fiber, Roughage
Dietary fiber is the part of plant foods the body cannot digest. It supports regular bowel movements, feeds beneficial gut bacteria, helps lower cholesterol and blood sugar, and promotes fullness. Values are set as Adequate Intakes based on 14 g of fiber per 1000 calories, which works out to about 38 g/day for adult men and 25 g/day for adult women, dropping after age 50.
Why it matters
What it does in your body
- Promotes regular bowel movements
- Feeds beneficial gut bacteria
- Helps lower LDL cholesterol
- Slows glucose absorption and steadies blood sugar
- Increases fullness and supports weight control
By age, sex, and life stage
How much you need
Fiber values are Adequate Intakes (AI), based on 14 g of fiber per 1000 calories consumed. For adults this is about 38 g/day for men and 25 g/day for women, dropping to 30 g/day for men and 21 g/day for women after age 50 as calorie needs fall.
Recommended intake across life
in grams/dayBars scale to the highest recommendation shown. Where men and women differ, both values are listed.
Full reference table
| Life stage | Male | Female |
|---|---|---|
| Children 1-3 | 19 (AI) | 19 (AI) |
| Children 4-8 | 25 (AI) | 25 (AI) |
| Ages 9-13 | 31 (AI) | 26 (AI) |
| Ages 14-18 | 38 (AI) | 26 (AI) |
| Ages 19-50 | 38 (AI) | 25 (AI) |
| Ages 51+ | 30 (AI) | 21 (AI) |
| Pregnancy | n/a | 28 (AI) |
| Lactation | n/a | 29 (AI) |
Values in grams/day. AI marks an Adequate Intake, used when there is not enough evidence for a formal recommendation.
What moves the number
What changes your needs
Calorie intake
The AI is based on 14 g per 1000 calories, so gram targets rise with a larger diet.
Age and sex
Men need more than women, and needs drop after age 50 as calorie needs decline.
Fluid intake
Fiber works best with plenty of water; too little fluid can worsen constipation.
Fiber type
Soluble fiber helps cholesterol and blood sugar; insoluble fiber supports regularity. A mix of plant foods provides both.
Running low
Signs you might not get enough
Most at risk: Very common. Most Americans get only about half the recommended amount, especially those eating few whole grains, fruits, vegetables, and legumes.
Too much
Can you get too much?
Problems come mostly from increasing fiber too quickly. Add fiber gradually and drink plenty of water to let the gut adjust.
Where to get it
Best food sources
The bottom line
Most people fall short. Build meals around beans, whole grains, fruits, and vegetables to reach about 25 to 38 g/day, and increase intake gradually with plenty of water.
Track dietary fiber automatically
Dietary Fiber is one of the 92 nutrients Vora reads from a photo of your meal, so you can see where you stand without weighing or logging by hand.
Sources and method
The recommended intakes, upper limits, and food-source amounts on this page come from the primary references below. Numbers were checked against the current NIH Office of Dietary Supplements fact sheets and the Institute of Medicine (now the National Academies) Dietary Reference Intakes.
- Institute of Medicine, Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2005)
- National Institutes of Health, Office of Dietary Supplements
This page is for general education, not medical advice. Reference intakes are population averages for healthy people and do not replace guidance from your doctor or a registered dietitian, especially if you are pregnant, managing a health condition, or considering supplements.