Adults need dietary fiber to promote health and improve digestion, but most people don’t get enough. It’s recommended that female adults receive between 22 and 28 grams (g) of fiber per day and male adults get 28 to 34 grams.¹

U.S. Department of Agriculture and U.S. Department of Health and Human Services. Dietary Guidelines for Americans, 2020-2025. 9th Edition.

Focusing on eating foods that are higher in fiber can help. Fiber supplements may also be appropriate for some people. Getting fiber from food is preferred because food also contains vital vitamins and minerals.

Daily Recommended Fiber Chart 

In general, it’s recommended that people get 14 grams of fiber per 1,000 calories of food they eat.² For anyone eating around 2,000 calories, that would be 28 grams of fiber a day, which would meet most recommended daily requirements.²

Unfortunately, most people don’t find it easy to get the recommended daily fiber intake. In fact, about 90% of women and 97% percent of men don’t eat the recommended amount of fiber daily.¹ Fruits and vegetables are a good source of fiber, but 85% of adults don’t eat the recommended daily amount.

These two statistics seem to suggest that people are not eating enough of the types of fresh foods that would help them achieve a diet that meets fiber goals.¹

The amount of fiber intake per day per sex and age group, as recommended by the Department of Agriculture (USDA), is shown in the following chart.¹

A Note on Gender and Sex Terminology

Verywell Health acknowledges that sex and gender are related concepts, but they are not the same. To accurately reflect our sources, this article uses terms like “female,” “male,” “woman,” and “man” as the sources use them.

Benefits of Dietary Fiber

The reason why there’s such a focus on getting the right amount of daily fiber is because it has so many benefits for overall health.

An extensive meta-analysis of 185 studies found that people who ate the highest level of fiber (between 25 and 29 g) were less likely to have certain conditions than those who ate the lowest amount of fiber. The decrease in the conditions that were tracked was anywhere from 15% to 30%. Some of the conditions included:³

• Colorectal cancer⁴
• Coronary heart disease
• Death after a stroke
• Type 2 diabetes

Eating a variety of foods high in fiber also benefits the following:

• Gut microbiome (the community of microbes that live in your gut)
• Colon health⁵
• Chronic constipation⁶
• Lower blood cholesterol levels,⁷ specifically low-density lipoprotein (LDL) levels⁸
• A feeling of fullness and potential weight loss⁹

Effects of Too Little Fiber

A low amount of fiber in the diet could lead to some health effects.

Diet can significantly affect digestion. For some people, too little fiber in the diet may lead to:

• Constipation (hard stools that are difficult to pass)
• Diarrhea (loose, watery stools)¹⁰
• Increased risk of colorectal cancer, coronary heart disease, stroke, and type 2 diabetes³

How to Up Fiber Intake 

After understanding how important fiber is to health, some people may want to increase their fiber intake. That can include adding more fibrous foods to the diet or taking fiber supplements. Fiber is found in plant-based foods, including fruits, vegetables, seeds, nuts, and whole grains.

Fiber should be gradually added to the diet over time to decrease the potential for side effects such as intestinal bloating and gas.

Here are some foods that are higher in fiber:

• 1 cup of cooked lentils: 15.6 g¹¹
• 1 cup of cooked split peas: 8.3 g¹²
• 1 cup of cooked black beans: 15 g¹³
• 1 cup of cooked pinto beans: 15 g¹⁴
• 1 cup of cooked kidney beans: 11 g¹⁵
• 1 cup of cooked edamame: 5.2 g¹⁶
• 1 cup of cooked chickpeas: 12.5 g¹⁷
• 1 ounce of dried chia seeds: 9.8 g¹⁸
• 1 medium apple with skin: 4.8 g¹⁹
• 1 cup of raspberries: 9.8 g²⁰
• 1 avocado: 13.5 g²¹

Fiber supplements are another way to increase fiber intake. However, not every type of fiber will work for every person. It may be necessary to try different types of fiber supplements to learn which one works well for digestion and doesn’t cause any unwanted effects.

The three types of fiber supplements have a main ingredient of psyllium, methylcellulose, or polycarbophil.

Whenever possible, the best idea is to get fiber from your diet. It’s also important to read labels on fiber supplements carefully. Some formulations may have additives such as artificial sugars, which could also lead to digestive symptoms in some people.

A Word From Verywell

It’s important to gradually increase fiber over the course of a few weeks. Along with gradually increasing your fiber intake, be sure to also increase your fluid intake. Adding more fiber without more water can actually worsen constipation.

— ELIZABETH BARNES, RDN, MEDICAL EXPERT BOARD

Summary

It’s important to include fiber-containing foods in the diet. This can mean eating fruits and vegetables as well as unrefined grains. Most adults in Western countries do not get enough fiber, which could increase the risk of certain health conditions.

Adding higher-fiber foods to the diet can increase fiber. Fiber should be added slowly to avoid gas and bloating. People with health conditions or conditions that restrict some foods may want to work with a healthcare provider to make a diet plan that meets all nutritional needs.

Sources:

1. U.S. Department of Agriculture and U.S. Department of Health and Human Services. Dietary Guidelines for Americans, 2020-2025. 9th Edition.
2. U.S. Department of Agriculture. How much (dietary) fiber should I eat?
3. Reynolds A, Mann J, Cummings J, Winter N, Mete E, Te Morenga L. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. Lancet. 2019;393:434-445. doi:10.1016/S0140-6736(18)31809-9
4. Gaesser GA. Whole grains, refined grains, and cancer risk: a systematic review of meta-analyses of observational studies. Nutrients. 2020;12:3756. doi:10.3390/nu12123756
5. Wilson AS, Koller KR, Ramaboli MC, et al. Diet and the human gut microbiome: an international review. Dig Dis Sci. 2020;65:723-740. doi:10.1007/s10620-020-06112-w
6. Bellini M, Tonarelli S, Barracca F, et al. Chronic constipation: Is a nutritional approach reasonable? Nutrients. 2021;13:3386. doi:10.3390/nu13103386
7. Soliman GA. Dietary fiber, atherosclerosis, and cardiovascular disease. Nutrients. 2019;11:1155. doi:10.3390/nu11051155
8. Evans CEL. Dietary fibre and cardiovascular health: a review of current evidence and policy. Proc Nutr Soc. 2020;79:61-67. doi:10.1017/S0029665119000673.
9. Harvard Health Publishing. Foods high in fiber: boost your health with fiber-rich foods.
10. Lambeau KV, McRorie JW Jr. Fiber supplements and clinically proven health benefits: how to recognize and recommend an effective fiber therapy. J Am Assoc Nurse Pract. 2017;29:216-223. doi:10.1002/2327-6924.12447
11. USDA FoodData Central. Lentils, mature seeds, cooked, boiled, without salt.
12. USDA FoodData Central. Peas, split, mature seeds, cooked, boiled, without salt.
13. USDA FoodData Central. Beans, black, mature seeds, cooked, boiled, without salt.
14. USDA FoodData Central. Beans, pinto, mature seeds, cooked, boiled, without salt.
15. USDA FoodData Central. Beans, kidney, all types, mature seeds, cooked, boiled, with salt.
16. USDA FoodData Central. Edamame, frozen, prepared.
17. USDA FoodData Central. Chickpeas (garbanzo beans, bengal gram), mature seeds, cooked, boiled, without salt.
18. USDA FoodData Central. Seeds, chia seeds, dried.
19. USDA FoodData Central. Apple, raw.
20. USDA FoodData Central. Raspberries, raw.
21. USDA FoodData Central. Avocados, raw.

Important Notice: This article was also published at www.verywellhealth.com by Amber J. Tresca where all credits are due. Medically reviewed by Elizabeth Barnes, RDN