High-Fiber Foods: 40 Ranked, Plus Which Feed Gut Bacteria

The highest high-fiber foods per portion are beans, peas and lentils, unsweetened bran cereal, artichokes, guava and berries: each gives 7 to 14 grams in a normal serving^[1]. Most adults are advised to eat 22 to 34 grams a day, depending on age and sex^[2].

Grams are only half the story. Different fibers feed different gut bacteria: inulin in onions and wheat, resistant starch in beans and cooled potatoes, beta-glucan in oats and barley^[3][4]. Below are 40 foods ranked by grams from USDA data, then which fiber types reach which microbes, and how to reach your daily target without the gas.

The 40 high-fiber foods, ranked by grams per portion

This high fiber foods list uses the standard serving size from the USDA and HHS "Food Sources of Fiber" table^[1]. Portions differ (half a cup of beans, a cup of vegetables), so compare the grams with the serving next to them. The last column names the main fermentable fiber that research links to each food, where a source we read identifies one^[3][4][5].

"Mixed fiber" means the food carries several fiber types and none of our sources singled one out. The USDA counts beans, peas and lentils as vegetables that can also count as protein foods^[1].

What are the top 10 high-fiber foods?

By grams per standard portion, the top 10 are bran cereal, lima beans, navy beans, artichokes, guava, green peas, split peas, raspberries, lentils and pinto beans^[1]. Seven of the ten are beans, peas, lentils or bran, which is why legumes are the most efficient way to raise your intake.

If you want the top 5 by food group instead:

• Most fiber in a legume: cooked lima beans, 13.2 g per cup.
• Most fiber in a vegetable (not counting legumes): cooked artichoke, 9.6 g per cup.
• Most fiber in a fruit: guava, 8.9 g per cup, with raspberries at 8.0 g.
• Most fiber in a grain food: unsweetened bran cereal, 14.0 g per half cup.
• Most fiber in a nut or seed: whole pumpkin seeds, 5.2 g per ounce^[1].

High-fiber foods by group

Beans, peas and lentils

High fiber legumes deliver 4 to 13 grams per serving^[1]. Cooked legumes and peas are also high in resistant starch, a starch that escapes digestion and is fermented in the colon^[4].

Worried about gas? Three feeding studies gave adults half a cup of beans daily for 8 to 12 weeks. In the first week, fewer than half reported more flatulence with pinto or baked beans, and only 19% did with black-eyed peas^[6].

High-fiber vegetables

The high fiber vegetables at the top are artichokes, green peas, canned pumpkin, Brussels sprouts and sweet potatoes, at 6 to 10 grams per cooked cup^[1]. Artichokes, asparagus, onions, garlic and leeks are natural sources of inulin-type fructans^[3]. In a USDA survey of more than 15,000 Americans, onions supplied about 25% of the inulin and oligofructose people ate, and wheat about 70%^[7].

Potatoes are a special case. A freshly baked potato's starch is mostly digestible, but cooking and then cooling starchy foods raises their resistant starch through a process called retrogradation^[4]. Potato salad and cold leftover potatoes are easy ways to use this.

High-fiber fruits

The high fiber fruits with the most grams per serving are guava (8.9 g per cup), raspberries (8.0 g), blackberries (7.6 g), pears (5.5 g each) and kiwifruit (5.4 g per cup)^[1]. Apples are a known source of pectin, and bananas carry both resistant starch and fructans^[3]. Eat the fruit rather than drinking it: 100% juice is lower in fiber than whole fruit^[2].

Whole grains and cereals

Unsweetened bran cereal tops the list at 14.0 g per half cup. Next come shredded wheat (6.2 g per cup), popcorn (5.8 g per 3 cups) and bulgur (4.1 g per half cup)^[1]. Oats and barley supply beta-glucan^[3]. In a meta-analysis of 28 trials, at least 3 g a day of oat beta-glucan lowered LDL cholesterol by 0.25 mmol/L^[8], which is relevant if you are working on high cholesterol.

Wheat bran is rich in insoluble arabinoxylan. In a 4-week trial in 60 healthy Japanese adults, cereal bars with wheat bran raised butyrate-producing bacteria and fecal butyrate compared with bars without it^[5].

Nuts and seeds

Seeds pack fiber into small portions: whole pumpkin seeds have 5.2 g per ounce, chia seeds 4.1 g per tablespoon and flax seeds 2.8 g per tablespoon^[1]. Almonds give 3.5 g per ounce. They work best as toppings for plant-based meals rather than as your main source; for the best high-fiber snacks to carry with you, see our list of high-fiber snacks.

Which fiber feeds which gut bacteria?

Human enzymes cannot digest most fiber, so it reaches the colon, where bacteria ferment it into short-chain fatty acids such as acetate, propionate and butyrate^[3]. Which bacteria do the work depends on the fiber's structure^[3].

Sources for the table: Holscher^[3], So and colleagues^[9], Birt and colleagues^[4], Whitehead and colleagues^[8] and Aoe and colleagues^[5].

A few named players: Ruminococcus bromii is enriched by resistant starch, and people without it have a reduced capacity to ferment that starch^[4][3]. Roseburia intestinalis, Faecalibacterium prausnitzii and Eubacterium species produce butyrate^[3]. The short-chain fatty acids they make activate cell receptors, inhibit histone deacetylases (enzymes that control gene activity) and serve as an energy source^[10].

A fiber that is selectively used by host microorganisms and confers a health benefit meets the scientific definition of a prebiotic^[11]. For the foods richest in those specific fibers, see our prebiotic foods guide.

What does a high-fiber diet do for your gut?

It shifts what your microbes do more reliably than which microbes you have. A meta-analysis of 64 trials in 2,099 healthy adults found that fiber raised Bifidobacterium and Lactobacillus and fecal butyrate compared with placebo or low-fiber diets, but did not change overall microbial diversity^[9].

A Stanford trial showed the same pattern. Adults doubled their fiber from 21.5 to 45.1 grams a day using legumes, seeds, whole grains, nuts, vegetables and fruits. Their microbes gained enzymes for breaking down fiber and their stools became softer, yet diversity stayed stable^[12]. In mice carrying human gut bacteria, a low-fiber diet caused losses that were reversible within one generation, but over several generations some bacteria disappeared and adding fiber back did not restore them^[13].

The benefits go beyond the gut. A Lancet review of 185 cohort studies and 58 trials compared the highest and lowest fiber eaters. The highest had 15% to 30% lower all-cause and cardiovascular mortality and lower rates of coronary heart disease, stroke, type 2 diabetes and colorectal cancer, with the largest risk reductions at 25 to 29 grams a day^[14]. In a trial in people with type 2 diabetes, a high-fiber diet promoted a select group of short-chain fatty acid producers, and people with more of them had larger improvements in HbA1c^[15].

Can high-fiber foods help with weight loss?

They may help, mainly by making a calorie-controlled diet easier to follow. In the POUNDS Lost trial of 345 adults on calorie-restricted diets, fiber intake was the most influential dietary predictor of weight lost over 6 months and of sticking to the diet^[16]. A 5-year cohort study measured belly fat with CT scans. Each extra 10 grams of soluble fiber a day was linked to a 3.7% slower build-up of visceral fat, though this was an observational link^[17].

The gut bacteria may play a part. When bacteria ferment fiber they make propionate. In a 24-week trial in 60 adults with overweight, 10 grams a day of a supplement that delivers propionate to the colon reduced weight gain and abdominal fat compared with inulin alone^[18]. That was a purpose-built supplement, not food, so treat it as a clue to the mechanism rather than a diet plan.

How can you get 25 to 30 grams of fiber a day?

Build each meal around one food from the top half of the table; no single food gets you there. US adults eat about 12 to 18 grams a day^[3], and more than 90% of women and 97% of men fall short of recommended intakes^[2].

The Dietary Guidelines set fiber goals at 14 grams per 1,000 calories. That works out to 28 grams for women aged 19 to 30, 25 grams at 31 to 50 and 22 grams at 51 and older; for men, 34, 31 and 28 grams^[2].

What does 30 grams of fiber a day look like?

Here is a day of high-fiber meals that reaches about 34 grams, the full daily goal for men aged 19 to 30, using USDA portions^[1]:

Swap freely within the table: black beans for lentils, a pear for the apple. For a lighter day of about 27 grams, drop the broccoli and the apple and add a quarter cup of prunes.

How can you increase fiber intake without gas and bloating?

The best way to increase fiber intake is to go up gradually and drink enough fluid. The NIDDK advises adding fiber a little at a time so your body adjusts, and drinking plenty of liquids to help fiber work^[19]. Some people have more gas when they eat too much fiber at once^[20].

1. Add one serving every few days. In the Stanford trial, people raised fiber over a 4-week ramp^[12].
2. Start with lower-gas foods. Legumes, cruciferous vegetables such as broccoli and cauliflower, apples, pears and whole wheat are common gas triggers^[20]. If one of them bothers you, use a smaller portion and build up rather than dropping the whole group.
3. Go easy on concentrated inulin. High doses of readily fermented fibers such as inulin can cause gas, bloating and diarrhea^[3].
4. Keep a food diary if symptoms persist. It helps a clinician or dietitian spot triggers, and people with IBS may be guided through a short low-FODMAP trial^[20].

Bean worries may be overstated. In the bean feeding studies, 3% to 11% of people reported more gas even on control diets with no beans, and the authors judged flatulence concerns exaggerated^[6]. If bloating is your main concern, start with smaller portions and build up.

If you are eating fiber specifically for constipation, our guide to high-fiber foods for constipation ranks the foods to reach for first and how fast fiber works. If a clinician has told you to eat less fiber for a procedure or flare, follow that advice; our low-fiber diet guide explains when it applies. For a wider look at foods that support the microbiome, including fermented foods, see the best foods for gut health.

This article is for general educational purposes and is not medical advice. Fiber values are standard USDA portions and vary by brand, variety and preparation, so check Nutrition Facts labels on packaged foods. Talk to a qualified healthcare professional before making major changes to your diet, particularly if you are pregnant, immunocompromised, taking prescription medication, or managing a diagnosed condition such as IBS or inflammatory bowel disease.