Melanie Clark, MS, RD, CSSD, LD, Well-Fit Sports Dietitian

Imagine not having to worry about GI issues on race day. Exercise induced gastrointestinal (GI) symptoms include bloating, gas, abdominal pain, vomiting or diarrhea.  Even minor GI symptoms can impact performance. As soon as they occur, the symptoms take your focus off racing/training. There are several nutrition related steps that you can take in training and the day leading up to the race to prevent GI issues. 

  1. Have a race day nutrition plan. 

Your plan should include what to eat and drink the day before the race, race morning, and during the race (for a personalized plan, check out Well-Fit’s Nutrition Coaching Packages). The day before your race is extra important if you are traveling because you may need to rely on food that you don’t typically eat. Locate restaurants and grocery stores near where you are staying. Having a race day nutrition plan will minimize risk of over or under consuming carbs and hydration, which can trigger GI symptoms. Aim to plan out your race nutrition at least a month before to allow time to practice it.

  1. Practice your race nutrition plan often.  

Just as you train your muscles, your gut also needs training. In fact, training your gut may improve delivery of nutrients during exercise. A study assessed a 10-day gut training protocol where athletes ran daily for 10 days at 60% VO2 max and consumed 90 grams of carbohydrates per hour while running (Costa, 2017). During a 2-hour run test following this 10-day gut training protocol, athletes had improved GI symptoms, reduced carbohydrate malabsorption, and improved running performance. While this study was in a lab setting and not a real race day scenario, it does show how training with carbohydrates often can improve tolerance and reduce risk of GI symptoms. 

  1. Drink water with sports gels and chews. 

Gels and chews are concentrated sources of carbs.  During intense exercise or racing, your gut will have a hard time digesting concentrated carbs. Typically, 8-10 oz of water for every one gel or three chews will lower the carb concentration, making it easier to absorb. When an athlete seeks out a dietitian for exercise induced GI distress it is commonly related to the carb concentration.

  1. Identify the ingredients in your sports products.

In sports products, such as gels, chews, and sports drinks, you will find glucose, maltodextrin, and fructose as some of the main ingredients. Your gut can break down and absorb about 60 grams per hour of glucose or maltodextrin and 30 grams per hour of fructose. View the images below as an example. If your sports product has a similar ingredient panel, then you can likely take in 60-90 grams per hour with no issues. If your ingredient panel does not list fructose, then stay at 60 grams of carbs or less per hour to avoid GI distress. If more carbs are taken per hour than you can digest, fuel will accumulate in your stomach and could result in bloating or vomiting.

There are countless sports nutrition brands and products available and there is no “best” product. The brands pictured are commonly found at races and therefore were chosen to be pictured as an example. 

  1. Limit fiber and fat 24 hours before your race. 

Fiber and fat are slow digesting types of foods and for some people can take 24 hours to fully digest. High fiber foods include beans, lentils, corn, flax seeds, whole grains, and some vegetables. High fat foods include fried food, cheese-based sauces, oils, and more. Focus on lean proteins, fruit, and low-fiber grains/starches the 24 hours before your race.