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Fiber 101

You’re probably aware that fiber is necessary for keeping the gut healthy — but did you know that fiber and gut health play important roles in your sports performance?

What is fiber?

Fiber is a type of carbohydrate that the body is unable to digest. Most carbohydrates are broken down into sugar molecules, but fiber passes through your body undigested. It helps regulate the body’s use of sugars — fiber is what keeps your hunger and blood sugar levels in check. 


There are two kinds of dietary fiber: soluble fiber and insoluble fiber. Soluble fiber dissolves in water, while insoluble fiber does not. Soluble fiber is what helps lower blood cholesterol and glucose levels. You can find soluble fiber in foods like nuts, lentils, oatmeal, beans, apples and berries. Insoluble fiber helps food move efficiently through your digestive system. It is what helps promote bowel regularity and prevent constipation. Insoluble fiber is found in foods like whole wheat bread, brown rice, legumes, carrots, cucumbers and tomatoes.


While fiber is found naturally in foods like whole grains, fruits, vegetables, legumes and nuts, it’s also commonly added to foods like cookies, cereals and granola bars. Chances are, you’ve probably seen a box of cereal or a snack food advertising “great source of fiber!” even though these foods actually contain little to no fiber naturally. The fiber in these products are typically isolated fibers that are synthetically made using chemicals. 

Why add fiber to these foods? According to the Food and Drug Administration (FDA), the Daily Value for dietary fiber is 28 grams per day; however, most Americans only get about 16 grams per day, as noted by the U.S. National Library of Medicine. Companies use added fiber to market their products as part of a gut-healthy diet. 

Fiber earned a good reputation for its digestive health benefits; however, fiber has benefits that extend beyond just gut health — such as sports performance. 

Fiber and sports performance

Fiber is necessary for your gut and digestive health, and your gut and digestive health are foundational building blocks of an active, high-performance lifestyle. Nobody wants to work out feeling bloated or full. It’s uncomfortable, slows you down and can get in the way of your workout — but fiber helps counteract this feeling. 


An increase in soluble fiber is linked to blood glucose stabilization, which means a more consistent energy supply. This is key for optimal performance. The short chain fatty acids making up fiber also directly affect glycogen release in the liver. The glycogen stores in the liver account for around 14% of the body’s available energy stores. 

Because fiber has such an impact on sports performance, Gainful offers a Fiber Performance Boost. This Performance Boost includes a scientist-recommended dosage of beta glucan, which is a heart-healthy soluble fiber that is derived from oat fiber. The Fiber Performance Boost rounds out a complete nutrition system, so athletes like you can get the nutrients you need to get the most from your workout.  

What are the benefits of fiber?

As noted above, fiber helps support your gut and microbiome health. It’s also able to help maintain regular bowel movement, maximize absorption of some minerals from food, support healthy blood sugar levels, promote heart health, lower cholesterol, curb appetite and support the immune system. Fiber’s role in digestion is linked to prevention of colon cancer. If you’re looking to lose weight, fiber’s slow rate of digestion and release of protein helps you feel fuller for longer and may prevent you from overeating. Fiber also has the ability to bind molecules, which may help decrease overall absorption of fat. 

There are a number of microorganisms that reside in our gut that are integral to maintaining a healthy immune system, and fiber is what feeds these microorganisms and allows them to do their job. Certain fibers (such as beta glucan, which is found in Gainful’s Fiber Performance Boost) are considered prebiotics — a.k.a. food for the probiotics that maintain healthy balances of bacteria.  

When to take fiber

Although fiber has many benefits for athletes, it does slow digestion, so it’s important to consider the fact that it may cause gastrointestinal distress if you have a low tolerance for fiber. To avoid any digestion issues during your workout, aim to take fiber a few hours before exercising (about two hours beforehand, to be exact).   


For sports performance purposes, consuming a scoop of Gainful Fiber Performance Boost at the same time you consume your personalized protein or hydration formula is recommended for optimal performance. You could also consume a scoop on its own with any drink in your day or sprinkle fiber over your food. 

It’s suggested to start with a half scoop to assess your tolerance for fiber and slowly build up to the full scoop. 

Can I take fiber if I am gluten intolerant?

There are many ways to get in fiber if you’re gluten-free. Beans like black beans, kidney beans and pinto beans are loaded with fiber. Leafy greens, such as spinach and kale, have tons of fiber, and vegetables like broccoli also contain fiber. 


When it comes to fiber supplements, be sure to read the label. Some fiber formulas — including Gainful’s Fiber Performance Boost — are not gluten-free.

Mental Health Benefits of Fiber

In addition to the physical benefits, fiber has mental health benefits: Researchers have found that people who get a proper amount of fiber have reduced feelings of anxiety and depression. Per the American Society for Microbiology, a diet with proper amounts of fiber can serve as a possible preventative strategy for depression, anxiety or other mental health disorders (though adjusting your diet is not a replacement for therapy and other tools for combating mental disorders). When levels of healthy bacteria in the gut are stabilized, the risk of mental health disorders such as depression are lowered — especially among postmenopausal women. 

Is fiber right for me?

Wondering if an extra dose of fiber is right for you and your performance goals? Find out by taking Gainful’s quiz. A team of experts review your answers and recommend formulas based on your body and your life. 


Fiber can provide additional nutrient absorption and satiation, allowing you to reach your fitness goals faster and more efficiently. Individuals who are limiting whole grains in their diet may experience B vitamin losses and fiber losses, so Gainful’s Fiber Performance Boost can help make up for the lack of fiber. From our Fiber Performance Boost to our protein powders, pre-workout and hydration formulas, each product contains science-backed ingredients that are added specifically for your needs. 


The Fiber Performance Boost is a testament to Gainful’s fierce commitment to personalization your way. It’s flexibly dosed based on your quiz answers and arrives to you where you need it and only when you need it, conveniently bundled with your subscription. You can expect clean ingredients made from trusted sources in every Gainful product, every single time. 


Take the quiz to add the Fiber Performance Boost onto your next Gainful order. Get ready to experience the benefits of a personalized nutrition system that includes the perfect amount of performance-enhancing fiber.