Everyone needs dietary fiber. It’s a nutrient found in plant-based foods best known for keeping your digestive system moving smoothly when it comes to eliminating waste. But, its job entails much more than that. First, let’s break down the different types of dietary fiber, what they do, and how much fiber you need.
What Is Fiber? And Why Do We Need It?
Fiber is a type of carbohydrate that the body can’t completely break down. When we eat carbs like bread, rice, and pasta, our digestive system breaks them down into sugars, which are then converted into energy. But in fiber’s case, it passes through the digestive system intact.
There are two types of fiber: soluble and insoluble. Each type is prominent in different foods, and fiber is only found naturally in plant-based foods.
Soluble fiber breaks down in water and is found in foods such as oats, beans, peas, carrots, blueberries, and apples.
Insoluble fiber does not dissolve in water. It helps move food through the digestive tract, which promotes good bowel health and prevents constipation. It is found in foods including whole grains, nuts, beans, potatoes, and vegetables.
Most plant-based foods contain both forms of fiber.
Fiber plays a number of roles in helping to maintain bodily functions, most notably keeping your digestive system in check. But, it also helps regulate blood sugar and makes us feel full and satisfied after meals.
How much fiber should you eat? According to the Mayo Clinic, women should eat at least 21 to 25 grams of fiber a day, while men should get 30 to 38 grams a day. (The average American gets about 15 grams of fiber daily.)
Let’s get more into how eating enough fiber can benefit our health.
Health Benefits of Eating Enough Fiber
It Promotes Good Bowel Health
Dietary fiber adds weight and bulk to stool, but it also softens it, making it easier to pass. It also helps maintain good bowel health. Eating enough fiber helps prevent constipation, which is when you’re not passing stools regularly. Constipation can usually be treated by increasing your fiber intake—aka eating more plant-based foods. But, chronic constipation can have some long-term effects, including hemorrhoids, fecal impaction (hard, dry stools in the rectum), and bowel incontinence.
Breaking it down further, some dietary fibers are prebiotics, which means they feed healthy gut bacteria. According to Katherine Harmon Courage, author of the book Cultured: How Ancient Foods Can Feed Our Microbiome, eating a wide variety of fiber is good for our gut. This is because there are many different types of fiber that gut microbes feed on during different stages of digestion.
“Lots of different kinds of fibers help lots of different microbes thrive and create different beneficial compounds for us,” Courage told NPR in 2019. “Which is good because we’re learning that generally, a more diverse microbiome is an indicator of health. If you look at people’s guts around the world — and even in the same society — people with more diverse microbiomes tend to be healthier overall.”
It Lowers Cholesterol Levels
Eating enough fiber is good for your heart. An umbrella review of 31 meta-analyses that compared the highest and lowest fiber intakes found significant reductions in the risk of developing and dying from cardiovascular disease when an adequate amount of fiber was consumed. This is likely linked to the fact that dietary fiber helps reduce cholesterol levels, a type of fat found in meat, eggs, dairy, and fish (which also don’t contain fiber). A high-cholesterol diet can be a risk factor for cardiovascular disease.
It Helps Control Blood Sugar Levels
Dietary fiber slows the absorption of sugar and fat in people with diabetes and therefore prevents spikes in blood sugar after eating. Multiple studies suggest that a high intake of dietary fiber also reduces insulin resistance and lowers the risk of type-2 diabetes. But, not just any form of fiber will do, according to an article published in the Journal of Nutrition. The lower risks are associated with high intakes of insoluble fibers, like whole grains and cereal fibers, rather than soluble fibers from fruits and vegetables. And, the lower risk of diabetes may be attributed to the other health benefits of whole grains. In short, further studies are needed to be certain about the connection between fiber intake and diabetes risk.
It Helps You Feel Full
High-fiber foods provide volume and also take longer to digest, which means you will feel satiated for longer periods of time after a fiber-rich meal.
And in 2014, scientists discovered that fiber contains an anti-appetite molecule called acetate. Acetate is naturally released when fiber is digested in the gut, and when it’s released, it signals our brains to tell us to stop eating.
It Helps You Live Longer
Several studies show that a high-fiber diet contributes to a longer life. In 2019, researchers from the University of Otago in New Zealand released a meta-analysis of clinical trials on fiber intake, spanning a 40-year period. Their review found that those with high-fiber diets have a 15 to 30 percent decrease in deaths related to heart disease, stroke, type-2 diabetes, and colorectal cancer.
First author Dr. Andrew Reynolds advises that whole grains are especially effective at lowering mortality risks from the causes of death studied.
“Fibre and whole grains are important physiologically, metabolically, and even to gut microbiome. Eating high fibre and whole grain foods is of a clear benefit to our health by reducing the occurrence of a surprisingly broad range of important diseases,” he said.
High-Fiber Foods to Add to Your Diet
What should you eat to add fiber to your diet? Try these foods:
Fruits and Vegetables
Get yourself a plate of grains, legumes, and vegetables for dinner and you’ll have one high-fiber meal in front of you. Try mixing up your dinners by buying a wide variety of vegetables: Broccoli, turnips, potatoes, sweet potatoes, cauliflower, green peas, and kale.
Fruits are also generally high in fiber, so they make a great snack (And, they also contain complex carbohydrates!), so keep things varied with berries, bananas, apples, oranges, and more.
Lentils, Beans, and Peas
Legumes, like lentils, beans, and peas, are high in fiber across the board. And since there’s so much variety, there’s less of a chance that you’ll get bored with serving yourself the same ol’ beans. Split peas rack up about 16 grams of fiber per cup, while kidney beans boast 11 grams of fiber per cup. Learn more about what makes legumes so healthy here.
(Nearly All) Whole Grains
Grains are awesome. They provide us with complex carbohydrates, which give the body energy and are known to help lower the risk of heart disease and type-2 diabetes Complex carbs are also generally high in fiber and keep us feeling satisfied for longer. Fiber-rich whole grains include whole-wheat pasta, barley, rolled oats, popcorn, quinoa (which is technically a seed), brown rice, and whole-wheat bread.
Nuts and Seeds
Adding nuts and seeds to your diet is another way to up your fiber intake. Almonds contain about 3.5 grams of fiber per ounce. Pistachios, sunflower seeds, chia seeds, and more are also good options. If snacking on nuts alone sounds boring, try a trail mix, like number 11 on this recipe list of lunchbox snacks—you don’t need to be a kid to love GORP, or any combination of fruit-and-nuts.