Running Smarter vol. 5
Training Your Gut: How to Avoid Digestive Distress on Race Day
Jennifer McDaniel, MS, RDN, LD Owner of McDaniel Nutrition Therapy
Corporate Wellness Dietitian | Speaker | Media Spokesperson | Author
Web: www.mcdanielnutrition.com
Instagram: @mcdanielnutrition @jenmcdanielrdn
Love You More Podcast: https://mcdanielnutrition.com/podcast/
Gastrointestinal issues are among the top reasons runners drop out of races, but just like building endurance, you can train your gut to handle nutrition during runs. Practice your fueling strategy in training—not on race day—so your digestive system adapts to the foods, gels, and drinks you plan to use. Avoid trying anything new when it counts; experimenting during a race often leads to distress. Aim to consume between 30 and 80 grams of carbohydrates per hour, adjusting based on your distance and personal tolerance. Mixing up carbohydrate sources—glucose, fructose, maltodextrin—can improve absorption and reduce upset, but be mindful if you’re sensitive to fructose, as it commonly causes discomfort. Proper hydration is essential, but also pay attention to the temperature and concentration of your fluids; very cold or overly concentrated drinks can aggravate the stomach.
What you eat the day before matters just as much as race-day nutrition—steer clear of high-fat, high-fiber, or foods that typically upset your gut, like dairy if you’re lactose intolerant. Avoid fats and fiber in your race fueling since they slow digestion and often cause irritation. The mind-gut connection is real: stress and anxiety can trigger GI symptoms, so finding calm before and during a race helps your gut stay settled. Medications, especially NSAIDs like ibuprofen, can also irritate your digestive tract during running, so use caution. Environmental factors such as altitude or heat may further affect digestion and hydration needs. If gut troubles persist despite your best efforts, consider consulting a sports dietitian or gut health specialist to develop a personalized plan. With the right preparation, your gut can be just as strong as your legs come race day.
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