What Does Fiber Do For the Body?

04.01.2026 | Category: Eating Well

Reviewed by: Dr. Manoj Pawar
Chief Medical Officer at Mutual of Omaha

Summary: A high-fiber diet supports digestion, heart health and blood sugar control, helping promote long-term overall wellness.

As we age, the daily habits that support digestion, heart health and steady energy become increasingly important. Getting enough fiber is one of the most overlooked parts of a healthy diet. The benefits of high-fiber foods go far beyond regulating digestion. High-fiber foods help lower cholesterol, manage blood sugar, support weight control and even contribute to healthier skin and a stronger immune system.

Key Takeaways

Fiber supports digestion, heart health and blood sugar control
High-fiber foods can help lower cholesterol and improve gut health
Gradually increasing fiber intake helps avoid digestive discomfort
Whole foods such as fruits, vegetables, beans and whole grains are the best natural sources of fiber
Small daily habits can make a meaningful difference in long-term health

What is dietary fiber?

Dietary fiber is a type of carbohydrate found in plant foods that the human body cannot digest or absorb. Unlike other carbs that quickly turn into sugar, fiber mostly passes through your digestive system, helping things run smoothly while supporting overall health. This is why fiber is essential for digestive health.

Types of fiber

Soluble fiber, which mixes with water to form a gel-like substance. It slows down digestion, which helps lower cholesterol and keeps your blood sugar steady. It can be found in oats, beans, apples and citrus fruits—all great high fiber foods packed with benefits.

Foods High in Soluble Fiber

Oats
Peas
Beans
Apples
Bananas
Avocados
Citrus fruits
Carrots
Barley

Insoluble fiber, which doesn’t dissolve in water. It adds bulk to your stool, making it easier to pass. This helps prevent constipation and regulates your digestive system. Whole grains, nuts, seeds and various vegetables are rich in this kind of fiber.

Foods High in Insoluble Fiber

Whole-wheat flour
Wheat bran
Nuts
Beans
Cauliflower
Green beans
Potatoes with skin

By including both types of fiber in your diet, you support smoother digestion and add foods that are beneficial for the heart to your meals. And if you find it tough to get enough fiber from food alone, high fiber supplements can help — remember to drink plenty of water to keep things flowing.

Why fiber becomes more important as you age

As people get older, maintaining digestive health, heart health and stable blood sugar levels becomes increasingly important. A fiber-rich diet supports all three.

Fiber can help regulate digestion, support healthy cholesterol levels and feed beneficial gut bacteria that influence overall metabolic health.

Small dietary habits can have long-term effects. Dr. Manoj Pawar, Chief Medical Officer at Mutual of Omaha, explains, “Choices made before age 40 significantly impact how quickly plaque builds up in your arteries (atherosclerosis), but every choice made after 40 still matters for your long-term health.”

7 health benefits of a high-fiber diet

Eating more fiber might seem like a small change, but it can have a big impact. From smoother digestion to a stronger heart and even healthier skin, the benefits of high-fiber foods touch nearly every part of your well-being.

1. Digestive health

One of the most immediate benefits of eating more fiber is improved digestive health. In a nationwide U.S. survey, Rome IV-defined chronic idiopathic constipation (CIC) was found to be common, affecting 6.0% of the population.¹ A high-fiber diet helps by adding bulk to your stool and speeding things up in your digestive tract.

Fiber also nourishes the beneficial bacteria that live in your gut, helping maintain a balanced microbiome. These microbes do more than support digestion. As Dr. Manoj Pawar explains, “Feeding your healthy gut bacteria with fiber produces byproducts that actively lower inflammation, blood pressure and cholesterol throughout the body.”

By supporting both digestion and gut health, fiber may help reduce the risk of issues such as diverticulitis and hemorrhoids, making it one of the most important nutrients for long-term digestive wellness.

2. Cardiovascular health

Soluble fiber attaches to cholesterol in the digestive system, aiding in its removal. Eating just 5 to 10 grams of soluble fiber per day can help reduce your LDL (“bad”) cholesterol.² Additionally, fiber-rich diets are linked to better blood pressure and circulation. ³

These are powerful fiber benefits that can help protect your heart and promote smooth digestion.

3. Weight management

Trying to manage your weight without always feeling hungry? Fiber can help. High-fiber foods take longer to chew and digest, which helps you feel full for longer. Both soluble and insoluble fiber are vital for optimal health and contribute significantly to the weight loss journey.⁴

4. Blood sugar control

Fiber slows the rate at which your body absorbs sugar, helping prevent blood sugar level spikes and crashes. A high-fiber diet is especially beneficial for people with diabetes or prediabetes, but it also supports steady energy for anyone throughout the day. Studies show that fiber-rich diets are linked to better insulin sensitivity and long-term metabolic health.⁵

5. Cancer prevention

A diet high in fiber is linked to a 17% lower risk of colorectal cancer, especially in people who regularly eat whole grains, fruits and vegetables.⁶The reason? Fiber helps move waste and potential toxins out of your body more efficiently. Additionally, antioxidant-rich high-fiber foods protect cells from damage, potentially lowering the risk of cancers such as breast and stomach.

6. Longevity and overall health

Regular consumption of high-fiber foods is strongly linked to reduced risk of early death and improved overall longevity, making fiber an essential component of a health-promoting diet. A fiber-rich diet helps protect against heart disease, diabetes and inflammation, giving you more energy now and better odds of staying healthy later.

7. Improved skin health

Apart from being beneficial for your gut health, fiber impacts your skin. By helping regulate blood sugar, fiber can help reduce breakouts and prevent other skin issues. Additionally, high-fiber foods are packed with antioxidants that support skin cell renewal and fight oxidative stress, supporting clearer, more vibrant skin over time.

How much fiber do you need?

The National Academy of Medicine⁷recommends getting following amount of fiber per day:

Women 50 years of age and younger: 25 grams
Women 51 years of age and older: 21 grams
Men 50 years of age and younger: 38 grams
Men 51 years of age and older: 30 grams

Examples of high-fiber foods

Adding more fiber to your diet is a great step, whether you’re aiming to support your heart, improve digestion or boost energy. And the best part? There are plenty of delicious ways to do it.

Here’s a breakdown of some everyday foods that pack a fiber punch. These are staples in a high-fiber diet and make it easy to enjoy the many high-fiber diet benefits without overthinking your meals.

Chart: Fiber content in common high-fiber foods

Fruits

Food Item	Serving Size	Fiber Content (grams)
Apples	1 medium	4.4
Pears	1 medium	5.5
Raspberries	1 cup	8.0
Bananas	1 medium	3.1

Vegetables

Food Item	Serving Size	Fiber Content (grams)
Broccoli	1 cup (cooked)	5.0
Carrots	1 medium	1.6
Turnip greens	1 cup (cooked)	5.0
Sweet Potatoes	1 medium	4.0

Legumes

Food Item	Serving Size	Fiber Content (grams)
Lentils	1 cup (cooked)	15.5
Split peas	1 cup (cooked)	16.0
Black Beans	1 cup (cooked)	15.0
Cannellini, Navy, Great Northern beans	1 cup (canned)	13.0

Whole grains

Food Item	Serving Size	Fiber Content (grams)
Quinoa	1 cup (cooked)	5.0
Oats	1 cup (cooked)	4.0
Brown Rice	1 cup (cooked)	3.5
Whole Wheat Bread	1 slice	2.0

Nuts and seeds

Food Item	Serving Size	Fiber Content (grams)
Chia Seeds	1 ounce	10.0
Almonds	1 ounce	3.5
Pistachios	1 ounce	3.0
Sunflower kernels	¼ cups	3.0

*Rounded to the nearest 0.5 gram.

*Source: Mayo Clinic, Chart of High Fiber Foods, 2025

Tip: Variety is key. Aim to include foods from each category throughout your day to obtain the full range of fiber benefits. High-fiber supplements can help fill in the gaps, but whole foods, which provide other nutrients, are always the best place to start.

Incorporating fiber into a gluten-free diet

A high-fiber diet has numerous long-term health benefits, and you can reap these benefits even if you’re following a gluten-free lifestyle. While whole grains like wheat and barley are typical fiber sources, gluten-free options such as quinoa, brown rice and gluten-free oats are also rich in fiber and just as effective.

Incorporating these gluten-free, heart-healthy foods into your diet supports digestive health, stabilizes blood sugar, aids in weight management and can even reduce the risk of colorectal cancer.

For those with gluten sensitivity or celiac disease, it’s best to focus on fiber-rich alternatives such as chia seeds, legumes and high-fiber fruits and vegetables to ensure adequate fiber intake without compromising digestive health.

How to add more fiber into your diet

Many people fall short of the recommended daily fiber intake, but small dietary adjustments can make a meaningful difference. As Dr. Pawar explains, “A simple way to eat better is to shop the perimeter of the grocery store, where you typically find fresh fruits, vegetables, fish, and lean meats rather than processed foods.”

Easy meal ideas

Start your day with high-fiber cereal or oatmeal topped with berries and chia seeds.
Add flaxseed or psyllium to smoothies.
Include beans, lentils, and veggies in soups, salads, or wraps.
Choose whole-grain bread, pasta, and rice over refined versions.

Snack Smarter

Grab an apple or a pear (with the skin on).
Munch on carrots, almonds, or popcorn.
Mix Greek yogurt with ground flax or sunflower seeds.

Make simple swaps

Use quinoa or brown rice instead of white rice.
Try legume-based pasta.
Swap mayo with mashed avocado or chickpeas.

Consider high-fiber supplements

If food sources aren’t enough, high-fiber supplements like psyllium may help. However, it’s important to:

Speak with your physician before introducing any new supplements into your diet.
Stay well-hydrated.

Dr. Pawar also cautions that while supplements can sometimes help, nutrients like potassium are typically best obtained from fresh plant-based foods because processing can degrade the quality.

Incorporating fiber into a gluten-free diet

Many naturally gluten-free foods are also excellent sources of fiber. While whole grains like wheat and barley are typical fiber sources, gluten-free options such as quinoa, brown rice and gluten-free oats are also rich in fiber and just as effective.

Incorporating these gluten-free, heart-healthy foods into your diet supports digestive health, stabilizes blood sugar, aids in weight management and can even reduce the risk of colorectal cancer.

Why is fiber important?

A fiber-rich lifestyle supports more than just your gut. It’s linked to better digestion, a healthier heart, steady blood sugar and easier weight management. Just a few of the many benefits of a high-fiber diet can make daily life feel better and brighter.

Instead of trying to overhaul your diet all at once, focus on small, consistent improvements.

Dr. Pawar emphasizes, “A successful health plan focuses on what is doable now. Small, steady wins are far more effective than trying to overhaul your entire lifestyle overnight.”

Adding fiber gradually and consistently can help build habits that support long-term wellness. Consistent habits around nutrition can support health at every stage of life.

At Mutual of Omaha, we’re committed to helping you protect what matters, including your health. From professional guidance to easy-to-use wellness tools, we’re here to support your journey every step of the way.

Visit Mutual of Omaha’s Medicare education to explore more ways to support your health and plan for the future.

Frequently asked questions about fiber

What happens if I eat too much fiber?

Too much fiber, especially added suddenly, can cause bloating, gas, cramps or constipation without enough water. Dr. Pawar advises to “go slowly, and be sure to drink a lot of water to help the fiber move through your system.”

What are high-fiber greens?

High-fiber greens include leafy vegetables like spinach, kale, collard greens and Swiss chard, which are packed with fiber as well as essential vitamins and minerals.

What is the #1 food high in fiber?

Beans and legumes are among the highest fiber foods you can eat.

How much fiber do you need to lower cholesterol?

Getting about 5 to 10 grams or more of soluble fiber per day can help lower LDL cholesterol levels.⁸

Explore 8 foods you can eat to help lower your cholesterol

What is the best fiber blood sugar control?

Foods high in soluble fiber, such as oats, beans, and citrus fruits, are especially helpful for blood sugar control. These foods work by slowing down digestion and the absorption of sugar in the bloodstream.

Reviewed by: Dr. Manoj Pawar

Chief Medical Officer at Mutual of Omaha

Dr. Manoj Pawar, MD, FAAFP, is a board-certified family physician and Chief Medical Officer at Mutual of Omaha. He brings over two decades of clinical and executive experience with a focus on preventive care, public health and empowering physicians and patients with the tools they need to live their best lives. Dr. Pawar completed his undergraduate degree at Northwestern University, his medical degree at McGill University in Montreal, and his specialty training at the University of Colorado. He’s a Fellow of the American Academy of Family Physicians, and a member of Delta Omega, the Public Health honor society.

Footnotes: