The Best Foods for Fiber: Support Your Health with Fiber-Rich Choices

Fiber is an important nutrient for overall health, but most of us aren't eating enough of it. More than 85% of adults don't meet the daily goal intake levels for the plant food categories rich in fiber, including fruits, vegetables, and whole grains. As a result, 90% of women and 97% of men don't meet the recommended daily levels of fiber intake, according to the 2020–2025 Dietary Guidelines.

To support your health, consider increasing your fiber intake by including more fiber-rich foods in your diet. Learn more about dietary fiber, its many health benefits, food sources, and tips to add more fiber to your diet below.

Understanding dietary fiber

Dietary fiber has varying definitions but is generally defined as complex non-starchy carbohydrates and lignin from various plants. Fiber does not contribute calories because humans can't digest it. Instead, fiber travels through the small intestine and arrives in the colon intact, where it is fermented by gut bacteria or passes through into our stools.

Food sources of fiber include only plant foods: fruits, vegetables, legumes, whole grains, and nuts and seeds. Fiber is not found in animal foods.

There are two types of fiber: soluble and insoluble fiber.

How much fiber do you need per day?

The American Dietary Guidelines recommend consuming 14 g of dietary fiber per 1,000 calories. Thus, a 2,000-calorie diet would require about 28 grams of fiber daily. A person with higher calorie needs would require more fiber proportionally.

Ideally, fiber intake would come first from whole food sources versus fiber supplements. In addition to fiber, foods high in fiber have vitamins, minerals, and other beneficial nutrients that support health synergistically.

Benefits of a high-fiber diet

Fiber has many potential health benefits, but health outcomes depend on the type of fiber, the amount consumed, and each individual person. Some potential benefits include supporting digestive health, cholesterol level management, and weight management through satiety regulation.

However, it's difficult to isolate the benefits of the fiber itself, as many studies include nutrient-dense foods that are high in fiber and contain other nutrients that may positively influence health.

Supports digestive health

Low levels of fiber intake may contribute to an increased risk of constipation, while adequate fiber intake can help with regular bowel movements.

In addition, a high-fiber diet may decrease the risk of diverticulitis, a condition where small pouches in the colon’s inner lining become inflamed or infected. As part of the Nurses' Health Study, which followed 50,019 women aged 43–70 between 1990 and 2014, researchers performed a prospective evaluation of dietary fiber, fruit, and vegetable intake using food frequency questionnaires.

They found that a higher fiber intake was associated with a reduced risk of diverticulitis. Fiber from fruits and cereals was inversely associated with diverticulitis. Though fiber may help decrease the risk of inflammation of the diverticula, it may not reduce the risk of forming the diverticula themselves, which is known as diverticulosis.

Helps manage cholesterol levels

The American Heart Association's 2021 Dietary Guidance suggests incorporating fiber-rich plant foods due to the inverse relationship between heart disease and dietary fiber intake from plants. However, research on fiber and its effects on cholesterol has been inconsistent.

Some studies have found that soluble fiber may have a small impact on lowering low-density lipoprotein (LDL) and total cholesterol. A low fiber diet may potentially increase the risk of coronary heart disease, a condition where the arteries that supply oxygen-rich blood flow to the heart become narrowed or blocked.

A systematic review that included 24 randomized controlled studies assessed the effect of whole grain foods on changes in total cholesterol, LDL (‘bad’ cholesterol), high-density lipoprotein (HDL, ‘good’ cholesterol), and triglycerides. Researchers found that whole grains, which are rich in dietary fiber, lowered total cholesterol and LDL, but the effects weren't directly connected to dietary fiber intake alone. In their analysis, whole-grain oat intake had the strongest effect on cholesterol and LDL.

Supports weight management

Dietary fiber intake may help you achieve a healthy weight. A positive relationship between dietary fiber intake and weight loss was found in a study on the effects of dietary fiber intake by the 4,477 participants in the 16-week Full Plate Living Program. Participants in the weight loss study group were educated to include more plant-focused fiber-rich foods over time to reach a goal of ~40 g of fiber per day, and they lost an average of 3.28 kg (~7 lbs).

Researchers found that the change in fiber intake from baseline to 16 weeks was a strong predictor of weight loss. However, participants were also encouraged to increase water intake, incorporate more physical activity, and were educated on fullness cues, so results may not be solely related to fiber intake.

Soluble fiber intake also may influence weight. A systematic review of 17 randomized-controlled trials investigated the effects of supplemental fiber on energy intake and perceived satiety, or feelings of fullness and satisfaction after a meal. Results suggested that supplemental soluble fiber may play a supportive role in weight management by:

• Helping increase satiety
• Decreasing hunger levels
• Decreasing gastric emptying time due to the viscosity of the soluble fibers, which helps contribute to feelings of fullness

High-fiber foods

Use the following lists of sources of dietary fiber to help you choose fiber sources to incorporate into your diet.

Fruits

Food	Serving size	Grams of fiber per serving
Guava	1 cup	8.9
Raspberries	1 cup	8.0
Blackberries	1 cup	7.6
Pear	1 medium	5.5
Kiwifruit	1 cup	5.4
Grapefruit	1 fruit	5.0
Apple, with skin	1 medium	4.8
Blueberries	1 cup	3.6
Mandarin orange	1 cup	3.5

Vegetables

Food	Serving Size	Grams of fiber per serving
Artichoke, cooked	1 cup	9.6
Sweet potato, cooked	1 cup	6.3
Parsnips, cooked	1 cup	6.2
Jicama, raw	1 cup	5.9
Broccoli, cooked	1 cup	5.2
Avocado	½ cup	5.0
Cauliflower, cooked	1 cup	4.9
Carrots, cooked	1 cup	4.8
Collard greens, cooked	1 cup	4.8
Kale, cooked	1 cup	4.7
Green beans, cooked	1 cup	4.0

Legumes

Food	Serving size	Grams of fiber per serving
Lima beans, cooked	1 cup	13.2
Navy beans, cooked	½ cup	9.6
Green peas, cooked	½ cup	8.8
Lentils, cooked	½ cup	7.8
Chickpeas (garbanzo beans), cooked	½ cup	6.3
Kidney beans, cooked	½ cup	5.7

Whole grains

Food	Serving size	Grams of fiber per serving
Ready-to-eat cereal, high fiber (example: bran)	½ cup	14.0
Ready-to-eat cereal, shredded wheat	1 cup	6.2
Popcorn	3 cups	5.8
Bulgur, cooked	½ cup	4.1
Spelt, cooked	½ cup	3.8
Teff, cooked	½ cup	3.6
Barley, pearled, cooked	½ cup	3.0
Crackers, whole wheat	1 ounce	3.0

Nuts and seeds

Food	Serving size	Grams of fiber per serving
Pumpkin seeds, whole	1 ounce	5.2
Chia seeds	1 tbsp	4.1
Almonds	1 ounce	3.5
Sunflower seeds	1 ounce	3.1
Pine nuts	1 ounce	3.0
Pistachios	1 ounce	2.9

Increasing fiber intake

Review your typical daily diet to see if you're eating enough fiber. If you don't regularly include fiber-rich fruits, vegetables, legumes, or whole grains, focus on the food group most lacking in your diet. For example, if you don't eat enough vegetables, incorporate ½ to 1 cup at lunch and/or dinner first. If you seldom eat whole grains, replace one serving of refined grains with one serving of whole grains, like replacing white rice with brown rice, white pasta with whole wheat pasta, or white bread with whole wheat bread.

Be careful not to increase your fiber intake suddenly. Instead, start adding high fiber foods to your diet slowly with one or two servings of high-fiber foods per day and ensure tolerance (i.e., no abdominal pain or increased risk of constipation) before increasing.

Take care to drink plenty of water and fluids when you increase your fiber intake, which will help the fiber move through your digestive tract.

Tips for fitting in more fiber

When working with clients as a registered dietitian, I focus on adding fiber-rich food options to meals and snacks and swapping low-fiber foods for high-fiber options. Here are some of my favorite tips for increasing daily fiber intake:

• Start your day by including a high-fiber whole grain at breakfast, such as a bowl of oatmeal, two slices of high-fiber whole grain bread, or a whole grain cereal with bran flakes or oat bran.
• Cook a large batch of whole grains at the beginning of the week to add to soups, salads, or as a side for a quick meal. Experiment with quinoa, barley, and/or bulgur and decrease your intake of refined grains over time.
• Add one serving of beans or lentils per day. Add ½ cup of kidney beans or lentils to salads for a fiber and protein boost, or try a cup of bean or lentil soup with lunch or dinner.
• Transition bread choices from refined white to 100% whole wheat or whole grain.
• Choose fiber-rich snacks when hungry between meals. Examples include a medium apple with 1 ounce of almonds, 100% whole wheat crackers with 1 oz cheese, or celery and carrots with a few tablespoons of homemade white bean dip.
• Include at least ½ cup serving of vegetables at lunch and dinner. Experiment with different cooking techniques to find the methods you like best, such as roasting, steaming, grilling, or braising. Raw vegetables, such as cucumbers, sliced pepper slices, or celery sticks, are great options, too.

Making a plan: how to meet the recommended fiber intake

To meet the daily recommended amount of fiber of 14 g per 1,000 calories, eat foods rich in fiber at most meals and snacks, as in the example below.

Daily meal and snack plan that provides 2,000 calories and 28+ g of fiber per day:

1. Breakfast: ½ cup of dry rolled oats cooked with 1 cup of non-fat milk and 1 teaspoon of chia seeds, topped with 1 teaspoon of honey, ½ cup of blackberries, and 1 tablespoon of walnuts.
2. Snack: 7-ounce cup of 2% Greek yogurt with 2 tbsp of granola and ½ cup of strawberries.
3. Lunch: 1 cup of vegetable barley soup, a salad with 1 cup of lettuce, 2 ounces of avocado, ¼ cup of tomatoes, and 2 tablespoons of olive oil-based dressing, with 1 ounce bread roll on the side.
4. Snack: ½ cup of raw carrot sticks and ½ cup of cherry tomatoes with 2 tbsp of garlic white bean dip.
5. Dinner: 4 ounces of boneless skinless chicken breast, 1 cup of sweet peppers and zucchini sauteed in olive oil, ¾ cup of brown rice or wild rice prepared with ½ tablespoon of butter, and 1.5 ounces of dark chocolate for dessert.

When to consider fiber supplements

Ideally, you would meet your fiber needs with a balanced diet that includes a variety of nutritious foods that are rich in fiber every day. However, this is not possible for everyone, especially for people with low appetite, a restricted diet, or some health conditions.

People who are consistently unable to meet their fiber goals from food may consider fiber supplements or fiber-fortified foods. Fiber supplements are sometimes helpful for people with constipation, too, though fiber-rich food choices should help relieve constipation over time.

Final word

Fiber has many potential health benefits, including improving cardiovascular and gut health, but most of us don't meet our daily dietary fiber goals. To increase your fiber intake, focus on including more whole food sources of plants in your everyday diet. Start by adding one to two servings of high-fiber foods daily and increase as tolerated until reaching the recommended fiber intake of 14 grams per 1,000 calories. Consult a healthcare provider if you're considering using fiber supplements.