Foods High in Fiber: Best Sources, Daily Needs and Tips

01What

What is fibre?

Dietary fibre is the part of plant foods that your body cannot digest. It passes through the digestive system, feeding gut bacteria, adding bulk to stool and affecting how quickly nutrients are absorbed. There are two broad types, and most plant foods contain both. A fibre-rich diet also tends to be rich in vitamins, minerals and antioxidants.

02Types

Soluble and insoluble fibre

• Soluble fibre dissolves in water to form a gel: found in oats, barley, beans, lentils, apples, citrus fruit, carrots and psyllium. It lowers LDL cholesterol and slows sugar absorption.
• Insoluble fibre does not dissolve: found in whole wheat, bran, nuts, seeds, vegetables and fruit skins. It speeds the passage of food and prevents constipation.
• Fermentable fibre and resistant starch (in legumes, cooled potatoes and rice, green bananas) feed beneficial gut bacteria.

03Needs

How much fibre do you need?

The US Dietary Guidelines recommend 14 g per 1,000 calories, which is about 25 g for women and 38 g for men up to age 50, and slightly less after 50 (21 g and 30 g). UK guidance recommends 30 g a day for adults. Most adults eat only 15–18 g. Children need less, roughly their age plus 5 g up to about 25 g.

04Legumes

Legumes: the fibre champions

• Lentils (cooked, 1 cup): about 15 g.
• Split peas (cooked, 1 cup): about 16 g.
• Black beans (cooked, 1 cup): about 15 g.
• Chickpeas (cooked, 1 cup): about 12 g.
• Kidney beans, white beans and edamame: 8–13 g per cup.
• Approximate values from USDA FoodData Central. Adding legumes to soups, salads and stews is one of the easiest ways to raise fibre.

05Grains

Whole grains, seeds and nuts

• Oats (cooked, 1 cup): about 4 g; barley (cooked, 1 cup): about 6 g.
• Whole wheat pasta (cooked, 1 cup): about 6 g; whole wheat bread: 2–4 g per slice.
• Quinoa and brown rice (cooked, 1 cup): about 5 g and 3.5 g.
• Chia seeds (1 tablespoon): about 4–5 g; flaxseed (1 tablespoon): about 3 g.
• Almonds (1 ounce, 28 g): about 3.5 g; popcorn (3 cups): about 3.5 g.
• Choose “whole grain” or “whole wheat” as the first ingredient on labels.

06Fruit and veg

Fruit and vegetables

• Raspberries (1 cup): about 8 g; pear with skin (1 medium): about 5.5 g.
• Apple with skin (1 medium): about 4.5 g; banana: about 3 g; orange: about 3 g.
• Avocado (half): about 5 g.
• Green peas (cooked, 1 cup): about 9 g; broccoli (cooked, 1 cup): about 5 g; artichoke (1 medium): about 7 g.
• Brussels sprouts, carrots, sweet potato with skin: 3–5 g per serving.
• Eat the skins where possible; fibre is concentrated there.

07Benefits

Benefits of a high-fibre diet

• Digestive health: softer, regular stools and lower constipation and haemorrhoid risk.
• Heart health: soluble fibre lowers LDL cholesterol; high-fibre diets are linked with lower risk of heart disease.
• Blood sugar control: slows sugar absorption and reduces the risk of type 2 diabetes.
• Weight management: high-fibre foods are filling.
• Gut microbiome and bowel cancer: fibre-rich diets are associated with lower colorectal cancer risk.
• See also alimentos con fibra (Spanish).

08Add

How to add fibre without bloating

• Increase gradually, by about 5 g a week, to let gut bacteria adapt.
• Drink plenty of water (fibre absorbs fluid).
• Swap refined for whole grains, and add beans to soups and salads.
• Eat fruit with skin and leave the peel on vegetables when appropriate.
• Add a spoon of chia, flaxseed or oats to yoghurt or porridge.
• Snack on fruit, nuts and vegetables with hummus.
• Rinse canned beans and soak dry beans to reduce gas.
• Exercise regularly, which also supports bowel function.

09Caution

Supplements and precautions

Fibre supplements (psyllium, methylcellulose, inulin) can help when diet is not enough, but whole foods offer additional nutrients. Some people with irritable bowel syndrome tolerate certain fibres better than others (soluble fibre such as psyllium is usually better tolerated than wheat bran). People with bowel strictures, obstructions, gastroparesis or inflammatory bowel disease flares may need to limit insoluble fibre. Too much fibre without enough fluid can worsen constipation. Always ask your doctor if you take medicines, as fibre can affect the absorption of some drugs, and take them at different times as advised.

10Cases

Three common situations

Constipation and low fibre intake: raise fibre gradually and drink more water, with prunes, oats and legumes.

Raised cholesterol: include oats, beans, lentils and fruit daily for soluble fibre.

Bloating after a sudden switch to a high-fibre diet: slow down, reduce portions, and build up over several weeks.

11Summary

Key points to remember

Aim for 25–38 g of fibre a day from legumes, whole grains, fruits, vegetables, nuts and seeds. Increase slowly with plenty of fluid and seek advice if you have a digestive condition. Our nutrition team can help you plan a fibre-rich diet that suits you.

This guide is for general information and does not replace an assessment by your own doctor, speech-language pathologist or dietitian.