Why Is Fiber Important for Your Digestive Health?

Fiber is a carbohydrate that the body cannot digest. Yet it is essential for digestive health, promoting regularity and preventing constipation. Fiber also slows down digestion and keeps blood sugar on an even keel.

Eamonn Quigley, MD, chief of gastroenterology and hepatology at Houston Methodist Hospital, says that intact microbiomes protect you from “bad bacteria” that may cause dysbiosis (imbalance) or infection.

“Your immune system is educated by the bacteria in your microbiome,” says Dr. Quigley. “And that’s how you learn to live with the microbes and how you learn to benefit from them.”

Read on to find out about good sources of fiber — and whether you are getting enough of it to fuel your microbiome.

Are You Getting Enough Fiber?

Quigley says that the long-term repercussions of a low-fiber diet on gut health can be significant, particularly if the pattern is established during childhood. “That’s a time where your microbiome is developing and you may cause changes that can be difficult to reverse,” says Quigley. “If you eat a low-fiber, poor-quality diet, you’re starving your microbes, and ultimately, that’s not going to have good consequences.”

How to Get More Fiber

The good news is that fiber is relatively easy to incorporate into your daily life, especially when you view it in the context of food, rather than focusing solely on the nutrient itself. A simple shift in perspective might be the catalyst you need to kick-start your journey toward a fiber-rich diet.

Kelly Kennedy, RDN, a program manager and dietitian for Bousquet Sport in Pittsfield, Massachusetts, and a previous manager of nutrition at Everyday Health, works with her patients to identify gradual strategies for including more nutrient-rich foods.

“I wouldn’t say, ‘You need to eat X, Y, and Z,’ because that doesn’t help people to be successful,” Kennedy says. “What would work for me wouldn’t necessarily work for another person. It has to be very personal.”

Kennedy encourages her patients to make small swaps that build fiber into their diets without eliminating foods they’ve grown up on or have always loved. For example, she might suggest substituting whole-wheat pasta for white pasta, or brown rice for white rice. She maintains a “progress over perfection” mindset.

“Continue to try new foods, try different brands, make a swap half of the time or even one-fourth of the time,” she says. “It doesn’t have to be perfect. It’s just about trying to improve and build on where you’re at now.”

Not All Fiber Is Created Equal

There are two main types of dietary fiber, soluble and insoluble, both of which should be part of your diet every day. Plant foods contain both soluble and insoluble fiber, but some are higher in one than the other.

• Oats
• Apples
• Nuts
• Seeds
• Legumes
• Berries
• Citrus fruits

• Whole grains
• Green beans
• Nuts
• Vegetables such as cauliflower, carrots, and potatoes

“Variety is just as important as getting enough fiber,” Kennedy says.

Easy Ways to Add Fiber

• Opt for whole fruits rather than fruit juices.
• Swap white rice, bread, and pasta for whole grains that are minimally processed, such as brown rice, whole-wheat bread, farro, and quinoa. Look for bread that lists “whole wheat,” “whole-wheat flour,” or another whole grain as the first ingredient. If it says only “wheat,” it isn’t a whole grain.
• Include high-fiber foods in your current meals by adding 1 to 2 tablespoons of slivered almonds or chia seeds to cereal, stirring more diced vegetables into casseroles, or substituting beans or legumes for meat in soups.
• Make snacks count by eating fresh fruits, raw vegetables, low-fat popcorn, whole-grain crackers, or nuts.
• Drink plenty of water to prevent constipation.
• Avoid added sugars — especially those that are refined, added, or processed — as much as possible. These do not benefit your gut microbiome.

What About Fiber Supplements?

Acknowledging the connection between fiber and a flourishing gut microbiome is the first step on a journey toward optimal gut health. A thriving gut, in turn, lays the groundwork for overall health and well-being. “I think we’re only just beginning to scratch the surface,” says Kennedy. “I think [the gut microbiome] is the future of nutrition and one of the most important things for people to focus on for good health.”