Dietary Fiber: Why It Matters and Easy Ways to Eat More

Fiber doesn't get as much attention as protein, but it plays an important role in how you feel every day. It supports regular digestion, helps you feel full after meals, and is part of eating patterns linked to better long-term health. Yet the Dietary Guidelines for Americans identify fiber as a nutrient most Americans don't get enough of.

Here's what fiber does and how to eat more of it — without upsetting your stomach.

What is dietary fiber?

Dietary fiber is the part of plant foods that your body can't fully digest. Instead of being broken down and absorbed like other nutrients, it moves through your digestive system and helps it work properly. There are two main types, and most plant foods contain a mix of both.

Soluble fiber

Soluble fiber dissolves in water and forms a gel-like material. It's found in oats, barley, beans, lentils, apples, citrus fruits, and carrots. According to MedlinePlus, soluble fiber can help lower cholesterol and blood sugar levels.

Insoluble fiber

Insoluble fiber doesn't dissolve in water. It adds bulk to stool and helps food move through your digestive system, which can help prevent constipation. Good sources include whole-wheat products, wheat bran, nuts, and many vegetables.

Why fiber matters

Fiber-rich eating patterns are associated with a range of benefits:

• Digestive regularity. Fiber helps keep bowel movements regular and can relieve constipation.
• Fullness. High-fiber foods tend to be filling, which can help with appetite control and healthy weight management.
• Heart health. Soluble fiber can help lower LDL ("bad") cholesterol.
• Blood sugar. Soluble fiber slows the absorption of sugar, which can help with blood sugar control.

How much fiber do you need?

The Dietary Guidelines for Americans set fiber goals based on age and sex — roughly 14 grams for every 1,000 calories you eat. For many adults, that works out to approximately:

• Women: about 22 to 28 grams per day
• Men: about 28 to 34 grams per day

Needs tend to be somewhat lower for older adults because overall calorie needs decrease. If you have a digestive condition, talk with your doctor or a registered dietitian about the right amount for you.

The best food sources of fiber

Beans and lentils are standouts: they're inexpensive, versatile, and provide both fiber and protein. Check the Nutrition Facts label on packaged foods — a product with 20% DV or more for fiber is considered a high source. Our guide on reading Nutrition Facts labels explains how.

10 easy ways to eat more fiber

1. Swap refined grains for whole grains. Choose whole-wheat bread, brown rice, or whole-grain pasta.
2. Start the day with oats. Top oatmeal with berries and a sprinkle of chia or ground flaxseed.
3. Add beans to what you already eat. Toss chickpeas into salads, black beans into tacos, or lentils into soup.
4. Keep the skin on. Eat apples, pears, and potatoes with the skin when practical.
5. Snack on whole foods. Try fruit, raw vegetables with hummus, air-popped popcorn, or a small handful of nuts.
6. Eat whole fruit instead of juice. Juice removes most of the fiber.
7. Fill half your plate with vegetables. It's the heart of a balanced plate.
8. Use frozen vegetables and fruit. They're convenient, affordable, and keep their fiber.
9. Read cereal labels. Choose cereals with more fiber and less added sugar.
10. Batch-cook grains and beans. Having them ready makes high-fiber meals faster. See our meal prep guide.

Go slow and drink fluids

Adding a lot of fiber all at once can cause gas, bloating, or cramping. To avoid discomfort:

• Increase gradually over a few weeks — for example, add one high-fiber food every few days.
• Drink plenty of fluids. Fiber works best when it absorbs water.
• Spread fiber across your meals rather than eating it all at once.

What about fiber supplements?

Fiber from whole foods is preferred because those foods also provide vitamins, minerals, and other beneficial compounds. Fiber supplements can be helpful for some people, but they can interact with certain medications and aren't right for everyone. Check with your doctor or pharmacist before starting one.

The bottom line

Fiber is one of the easiest nutrition upgrades you can make. Build meals around vegetables, fruits, beans, and whole grains, increase your intake gradually, and drink plenty of fluids. Small swaps — like oats for breakfast or beans in your soup — add up quickly.