Updated 18th September 2025
Sports nutrition: Could fiber improve your performance?
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Whether you’re an avid sports person or just a recreational athlete, you probably pay close attention to your diet, and in particular, the amount of protein and carbs you consume.
Protein is vital for building almost all of the structures in your body, but its role in muscle building is most well-known. As for carbs, we know they provide the energy we need to perform at our best.
However, little is said about the importance of dietary fiber in athletes and those who are physically active.
The only fiber recommendation from the American College of Sports Medicine is to limit fiber intake just before exercise because it reduces the risk of gut symptoms during exercise.
This makes sense, but there’s no mention of how much fiber should be consumed as part of your regular diet.
In this article, we’ll explore the importance of dietary fiber for everyone, regardless of activity levels. But we’ll also cover some research suggesting that adequate fiber intake might benefit athletic performance.
Finally, we’ll talk about components of plants other than fiber and how they might also improve your physical performance.
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Fiber: The overlooked macronutrient
Walk into virtually any grocery store, and you’ll see countless products labeled as high-protein. These products are popular with many consumers, especially those who are trying to build muscle.
However, this protein craze is nothing more than a marketing ploy designed to lure money away from people who are trying to get fit.
While older adults, young children, and people who are very physically active might need to keep an eye on their protein intake, the vast majority of adults already consume adequate amounts.
That’s why you never hear of anyone being protein-deficient outside of acute illness, chronic undereating, or lower-income countries.
If you’d like to know how much protein you need, you can find ZOE’s personalized protein guide here.
When it comes to dietary fiber, however, nearly all of us — more than 95% — don’t consume enough. So, why is fiber so important? Here are just some of the benefits:
It helps promote regular bowel movements.
It feeds your gut microbiome, which supports overall health.
A fiber-rich diet can help lower blood cholesterol levels.
Consuming adequate fiber is associated with a lower risk of heart disease.
Higher fiber intake is linked to a lower risk of some cancers.
If you’d like to dig deeper into the benefits, read this article explaining the importance of fiber.
How much fiber do athletes consume?
Experts recommend that we consume around 30 grams of fiber per day, but in the United States, adults consume just 16–18 g.
Fiber is present in all plants, so if you focus on eating a varied, plant-based diet, this is fairly easy to achieve.
But in the West, well over half of our calories come from highly processed foods, which rarely contain any fiber at all.
For some delicious high-fiber options, here’s a list of 29 high-fiber foods to get your juices flowing.
Sportspeople also tend to consume below the recommended amount of fiber. Although there hasn't been a lot of focus on fiber intake in athletes, studies have found that:
Endurance athletes in the U.S. consume an average of 25 g per day.
High levels soccer players in Italy consume around 16 g per day.
Distance runners in South Korea consume 17 g each day.
Basketball and softball players in the U.S. consume 17–18 g per day.
Soccer players in Australia consume an average 27 g per day.
Can upping fiber intake improve athletic ability?
There has been very little research on this question. However, studies already show that fiber is vital for cultivating a healthy gut microbiome and that a healthy gut is linked to improved overall health.
Also, some research in adults aged 40 or older has shown that a high-fiber diet is associated with better body composition, including more muscle mass.
Although this study wasn’t in athletes, it hints at a role of dietary fiber in protecting muscle as we age.
So, while research is ongoing, it seems likely that consuming adequate fiber is likely to benefit athletic performance in some way.
Research also shows that high-protein diets, which are common among highly active people, have a negative impact on the gut microbiome.
Specifically, there is a decline in some “good” bacteria, like Bifidobacteria and other species that produce short-chain fatty acids (SCFAs).
SCFAs provide energy to the cells that line your gut, help you absorb minerals more easily, reduce inflammation, and much, much more. They are one of the reasons that looking after your gut health is so important.
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So, for athletes on a high-protein diet, increasing fiber intake might help offset these changes because fiber feeds “good” bacteria. And some experts believe that SCFAs produced in response to dietary fiber could support performance.
As we mentioned, SCFAs provide energy to your gut lining, but some SCFAs also enter your blood and provide fuel to cells in other parts of your body.
In fact, SCFAs may account for around 10% of your daily energy needs, so they have the potential to give you extra fuel when you need it.
A review on SCFAs and exercise in BMJ compiled the results of animal and laboratory studies.
The authors concluded that, via multiple pathways, SCFAs may “contribute to efficient energy metabolism and are thus key to maximising substrate utilisation in endurance exercise.”
Aside from possibly providing energy, the anti-inflammatory effects of SCFAs might help speed up recovery after exercise and play an important part in muscle metabolism and growth.
Athlete’s gut
Unpleasant gut symptoms are common in athletes. Known as exercise-induced gastrointestinal syndrome, it’s defined as “disturbances of gastrointestinal integrity and function that are common features of strenuous exercise.”
One reason for this syndrome is that when we exercise intensely, blood is shunted to our muscles, meaning that less is available for the gut.
So, if we exert our bodies for long periods, it can start to damage the gut lining.
As we mentioned, SCFAs help support your gut lining, but bacteria that produce these compounds tend to be reduced in athletes.
So, it is also plausible that increasing fiber intake to support the growth of “good” gut bacteria could help reduce this issue and speed up the healing of your intestines.
Fiber and sleep
Getting good sleep is vital for improving your athletic performance, but many athletes struggle to get enough good-quality shut-eye.
Perhaps fiber might help here, too. There’s some evidence that higher fiber intakes are associated with better sleep quality and a reduced risk of sleep disorders.
Once again, experts believe this might be due to an increase in microbes and the SCFAs that they release.
What’s beta-glucan?
Beta-glucan is a type of fiber linked to specific health benefits, such as lowering cholesterol levels.
It’s found in oats, barley, rye, maize, wheat, mushrooms, and seaweed, among other plants. And some research suggests that it has health benefits that are relevant for athletes.
For instance, one study concluded that upping intake improves muscle strength and exercise capacity, and another found that it reduced inflammation during recovery after exercise.
A quick note on supplements
Today, there is a wide range of fiber supplements on the market. Most often, these only contain one form of fiber.
But there are thousands of different types of fiber, and different species of bacteria prefer different types.
That’s why, at ZOE, we advocate for a whole-food diet rich in a wide variety of plants, including nuts, seeds, pulses, and legumes.
Following this pattern guarantees you get all the nutrients you need and a good variety of fiber types.
Consuming fiber in whole foods also means you benefit from the other healthy compounds in plants.
Famously, plants are rich in vitamins and minerals, but they also contain other compounds that may support physical activity, such as…
Phytonutrients: An extra boost?
Phytonutrients are compounds produced by plants. Some, such as polyphenols, are defensive chemicals that protect plants from infectious disease and the sun’s damaging UV rays.
Other phytochemicals discourage herbivores and attract pollinators.
Some research suggests that phytonutrients, when consumed, might improve brain function in ways that support athletic performance, although detailed research on the topic is lacking.
However, there is fairly robust evidence that phytonutrients, particularly polyphenols, act as antioxidants, support heart health, and reduce inflammation.
All of these could support long-term physical performance and recovery after training.
Additionally, there is some evidence, although from relatively small studies, that tart cherry and beetroot might aid recovery after exercise. Scientists presume this could be due to the bioactive phytonutrients, including polyphenols.
If you want to up your polyphenol intake, this article provides 10 healthy sources.
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What should you do?
Everyone can benefit from increasing their fiber intake. And if you’re involved in physical activity, it might just give your performance a slight boost.
However, if your current diet is low in fiber, it’s important to increase your intake slowly. If you go too hard at the start, you might experience uncomfortable bloating and excessive gas.
This will pass over time as your microbiome adjusts, but by gradually upping your intake, you can avoid these symptoms.
All plants contain fiber, and different types of plants house different forms of fiber, so aim to eat as wide a variety as you can.
And try to eat the rainbow: Different colored fruits and veggies contain different levels of phytochemicals and polyphenols.
Finally, if you want to track your fiber intake, it can be challenging. However, ZOE's new app makes it much easier. Simply snap a photo of a product or meal, and it will tell you how much fiber it contains, allowing you to track your intake over the day. Download it here.
If you want to start your fiber journey, ZOE has many recipes that are fiber-packed and simple to make. We also have this handy guide to help you get started.
