Is There a Link Between Gut Health and Athletic Performance?

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A break down of all things gut health – why gut health is important, what foods are good and bad for gut health, and the relationship between the gut and exercise.

Gut health has become a trending topic in the nutrition and fitness world. And with good reason, since many studies suggest that the tiny microbes in the gut play a huge role on overall health. But only recently have scientists started to wonder about the connection between gut health and athletic performance. Although the research is limited, there are promising results suggesting that the health of your gut may impact how you feel while working out.

gut health

Why is gut health important?

The gut microbiome is made up of trillions of microorganisms, mainly bacteria, that play a key role in the digestion of food and absorption of nutrients. These microorganisms are also involved in metabolism, body weight, immune regulation, brain function and mood. Our gut contains both good and bad bacteria, and many factors (like diet, stress, sleep patterns) influence the type and amount of bacteria in our gut. 

The gut is, in fact, an organ and plays an important role in how you metabolize and utilize the nutrients in food. Athletes place a lot of focus on what to eat, but you may lose out on important nutrients if you don’t digest and metabolize them properly. 

The gut microbiota are responsible for the production of short chain fatty acids (SCFA), which may play a role in muscle recovery and energy levels during exercise. SCFA can be made from all carbohydrates, but mainly from prebiotic dietary fiber.

Prebiotics are foods (typically high in fiber) that feed the good bacteria in your gut, allowing them to flourish. In other words, prebiotics are great for improving the balance of healthful bacteria in your gut and are linked to improved gut health. 

By eating foods that allow healthy bacteria to thrive, like fiber-rich fruits, vegetables, beans, legumes and whole grains, carbohydrate metabolism and SCFA production increase, leading to numerous health benefits (especially for athletes) such as greater muscle turnover and recovery, and keeping energy levels up.

How does gut health affect athletic performance? 

You already know that a healthy and diverse microbiome promotes the production of short chain fatty acids, which may enhance muscle recovery and performance. But let’s take a deeper dive into this relationship between the gut and exercise. 

Exercise has numerous benefits on gut health, but it’s not a one-way relationship! Our gut microbiome can also improve our athletic performance. During exercise, the gut microbiota is stimulated to produce a specific SCFA, called butyrate. 

Butyrate reduces gut permeability and fights inflammation. Simply put, when the barrier of the intestines is less penetrable, essential nutrients can be absorbed easily and pathogenic organisms and harmful bacteria are blocked from passing through our intestines. Butyrate also fights off the ‘pro-inflammatory’ substances, which prevents inflammation. 

A healthy gut microbiome is also beneficial during exercise because it helps supply muscles with necessary nutrients and oxygen. When the gut bacteria break down and digest carbohydrates, they produce SCFA which can be further broken down into glucose.

As you probably know, glucose is the main fuel source during exercise. Having more glucose in the body reduces the time to fatigue and allows you to work out for longer. 

Gut health is also directly linked to our hydration status. A healthy gut microbiome is better able to use water efficiently and control the transport of electrolytes through the gut lining. Being adequately hydrated is a key component of overall performance. You cannot perform at your best if you are dehydrated, and dehydration can be dangerous. 

Last, but not least, the gut microbiome is able to regulate hormones, like serotonin, GABA and cortisol, which are involved in our sleep cycles. A healthy gut can lead to a better night’s sleep. It is no surprise that getting adequate sleep is essential for athletic performance.

woman running on sunny trail

How athletes can build a healthy gut

To build a healthy gut, focus on what you are putting on your plate. Our good gut microbes thrive on a diet that consists of prebiotic and probiotic rich foods. Of course, there are certain foods that contain these two types of nutrients, but a diet that includes whole grains, legumes, fruits, vegetables, nuts, and seeds is most beneficial.

In addition, foods that are rich in plant compounds, called polyphenols, may also have a positive impact on the gut microbiome. This list includes berries, leafy greens, cocoa, dark chocolate, tea and even red wine. 

If you are underfueling and restricting certain macros, the good gut microbes won’t have the fuel they need to survive. In addition, any excessive bodily stress can harm your gut microbiome, due to the cortisol or any other stress-related hormones that are released. Over-training or not allowing adequate recovery time is unnecessary stress that may be disruptive to your gut health. It goes without saying the importance of rest days and resisting the urge to overtrain. 

Food for a healthy gut

Generally speaking, good gut health promotes a diverse microbiome. To achieve this diversity, you need to incorporate a wide variety of foods in your diet. Each type of food contributes a different species of bacteria to your gut. 

As stated earlier, focus on foods that are as close to their natural form as possible. This usually includes: 

  • Whole grains 
  • Nuts
  • Seeds
  • Legumes
  • Beans
  • Fruits
  • Vegetables

Vegetables, fruit, legumes and beans are known for their high-fiber content – and while fiber cannot be digested in our GI tract, the bacteria in our gut are able to break it down and use it for energy to stimulate their growth. Many fruits, vegetables and whole grains also contain prebiotics – these are fiber or complex carbs that the healthy bacteria feed off to grow in number. 

Some athletes are hesitant to include more fibrous foods into their diet because of the unpleasant side effects that are associated with them (like gas and bloating). If this is the case for you, try increasing your fiber intake gradually over time. 

Fermented foods like yogurt, kimchi, sauerkraut and tempeh contain live cultures that enhance the microbiome. Be sure to choose fermented foods with minimal or no added sugar, because sugar can be harmful to the gut. 

Here are some naturally probiotic rich recipes to try: 

Another great addition to your diet are prebiotics. Prebiotics are in foods such as whole grains, bananas, greens, onions, garlic, soybeans, apples, flaxseeds, asparagus and artichokes. 

Generally, a plant-based diet is associated with better gut health. A study showed that high intake of animal products, processed foods, alcohol and sugar, creates a microbiome that encourages inflammation, while a diet rich in plant-based foods promotes a gut that is more abundant in healthful bacteria. 

Research has also determined that eating a Mediterranean Diet is good for the gut. That translates to a diet full of fresh fruits and vegetables, healthy oils, nuts, seeds, legumes, beans and fish. 

colorful fruits and vegetables

Foods that are bad for the gut

Unfortunately, the American diet is full of processed foods that affect the microbes in the gut. Because probiotics have evolved to break down whole foods, eating a diet high in processed foods causes undesirable effects in the microbiome.

Specifically, foods that are high in saturated fats, like red meat, and foods that are rich in refined carbs and sugar, such as chips and desserts, can cause unwanted microbiome factors. Many processed foods also contain artificial sweeteners, which have been shown to affect the good bacteria in the gut. Not to mention that the average American diet contains 150 pounds of sugar per year! 

foods that are bad for gut health

The bottom line

The health of your gut plays a role on athletic performance. It’s difficult to assess since each person’s gut varies so greatly. But eating a well-balanced plant-based diet with plenty of probiotic and prebiotic rich foods will help you achieve your performance goals. 


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I’m Natalie Rizzo, an NYC-based Registered Dietitian.

My mission is to help everyday athletes fuel their fitness with plants.

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