Why Is Fiber So Important?

If thinking about fiber calls to mind sad, bland bran flakes and, well, pooping a lot, it’s time to rewrite the narrative. Fiber is a critical element of a healthy diet, and it does all kinds of important things for your body, including but certainly not limited to keeping you regular.

So, what does fiber do? Registered dietitian Beth Czerwony, RD, explains.

What is fiber?

“Fiber is a type of carbohydrate that your body can’t break down,” says Czerwony. And while that sounds like it could be a bad thing, fiber is actually something your body really needs.

There are two types of fiber: soluble and insoluble (or non-soluble). They serve similar but slightly different functions in your body and can be found in a variety of foods.

• Soluble fiber can be dissolved in water. “This type of fiber has been shown to help with constipation, stabilize blood sugars, lower cholesterol levels and manage weight,” Czerwony says. It’s found in the flesh of some fruits and vegetables. Good sources include konjac, oat bran, dry oats, barley, nuts, beans, lentils and peas.
• Insoluble fiber can’t be dissolved in water. “It helps move food down the gastrointestinal tract, which also helps relieve or prevent constipation,” Czerwony explains. Insoluble fiber is found in the skin, strings and seeds of fruits and vegetables, including nuts, seeds, corn and kale.

What does fiber do for your body?

Nutrition experts rave about fiber — and for good reason. Here are the ways fiber benefits your body.

Keeps your digestive system working properly

The bad news? Your digestive system can be finnicky. You may experience diarrhea one day, constipation the next day. And you may have been diagnosed with irritable bowel syndrome (IBS).

The good news? Fiber can help keep things moving along your digestive system, keeping your bowel movements more regular. Fiber bulks up and softens your poop, which makes it easier to go to the bathroom.

Lowers cholesterol

A diet high in fiber can help lower your LDL (“bad”) cholesterol — especially foods with soluble fiber, which may stop your body from absorbing the bad cholesterol you eat in other foods.

“Soluble fiber binds with cholesterol and bile acids in the digestive track, preventing it from being absorbed into the bloodstream,” says Czerwony.

Improves blood sugar

If you have prediabetes or diabetes, your healthcare provider will more than likely talk to you about the importance of fiber. And the reason? Fiber slows down how quickly your body digests food, as well as its glucose absorption.

“Soluble fiber slows down how fast the stomach digests, allowing small bursts of energy to be released into the blood stream, which allows the body to process it slowly,” explains Czerwony. “Soluble fiber also turns into a gel-like substance in the GI track, which slows down the digestion of carbohydrates.”

Lowers your risk for certain diseases

“Research shows that in countries where people consume high amounts of fiber in their diets, the overall rates of chronic disease are low,” Czerwony notes.

Fiber may lower your risk of:

• Colorectal cancer
• Gastrointestinal issues like diverticulitis, constipation and hemorrhoids
• Heart disease
• High blood pressure
• Obesity and overweight
• Stroke
• Type 2 diabetes

Keeps you fuller longer

A high-fiber diet also keeps you feeling fuller for longer, which is linked to lower body weight and aids in weight management. In fact, soluble fiber reduces your body’s capability to absorb fat, while insoluble fat helps your body process water more efficiently.

“Fiber can be helpful in weight management by promoting a feeling of fullness sooner and longer, allowing you to eat less and less often,” says Czerwony. “Regulation in blood sugars also helps reduce appetite.”

Bottom line?

For most of us, it’s important to add more fiber to our diets. It’s best to get your fiber from the foods you eat (known as dietary fiber), but you may want to consider adding a fiber supplement.

Regardless of where you get your fiber, Czerwony stresses the importance of taking it slow.

“Add in fiber slowly — if added too quickly — you can either have GI issues like bloating, gas, diarrhea until your gut microbiome is adjusted,” concludes Czerwony.