Gut training and endurance sports

When athletes prepare for an endurance event, their focus revolves around planned workouts to build endurance and speed, drills to refine technique, and other essentials for competition. As the event approaches, race day nutrition becomes crucial. However, one often-overlooked aspect is gut training.

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''Experiment during training to optimize your race day nutrition strategy''

What Do We Mean by “Gut”?

The gut refers to the digestive tract, including the stomach and intestines. It functions as an internal highway breaking down food, extracting nutrients, and providing energy, akin to a fuel station replenishing your body's energy tank.

Why Train Your Gut?

A well-functioning gut is vital for delivering nutrients during exercise and preventing gastrointestinal problems. Since carbohydrates are endurance athletes' primary fuel source, there's a trend towards higher carbohydrate intakes during events to enhance performance. However, this requires training. Waiting until race day to consume carbs during exercise can lead to gastrointestinal distress—cramps, bloating, and urgent bathroom breaks. Training your gut with higher carb intakes can reduce distress during races.

How To Train Your Gut

Incorporate easily digestible carbs into longer training sessions simulating race conditions. Regular consumption of carbs like fruit bars or sports drinks helps your gut process and absorb carbs efficiently during exercise, reducing the risk of distress during the event.
Consider ingesting smaller, more frequent carb-rich snacks or drinks to maintain steady energy levels and optimize absorption. Experiment with timing intervals based on terrain and intensity. Experiment with timing intervals to find what works best for your body and the specific demands of the event—whether you’re tackling uphills, downhills, or flat terrain..

  • Carb Intake: The amount of carbs needed depends on event duration and intensity. Gradually increase carb intake during training to condition your gut. Up to 60g/hour is recommended for exercise lasting around 2 hours. Research suggests that higher intake rates may further enhance performance during longer events. Some athletes (e.g. World Tour cyclists) are ingesting upwards of 100g carbs/hour. In ultra-endurance events where the intensity is lower, carbohydrate needs will vary.
  • Carbohydrate Sources and Gut Absorption: Experiment with different carbohydrate sources to find what your gut tolerates best. Different sugars, such as glucose and fructose, use distinct transporters, optimizing uptake and providing sustained energy during endurance exercise. Some ultrarunners opt for a variety of whole foods, such as bananas, dates, and sweet potatoes. Avoid high-fiber, high-fat, and high-protein foods both before and during exercise.
  • High Carbohydrate Diet: Consuming a high-carb diet enhances the gut's ability to absorb carbs by increasing transporter density in the intestine. Focus on healthy complex carbs like legumes, starchy vegetables, and whole grains, benefiting overall health and replenishing muscle glycogen stores for subsequent training.

In summary

Training your gut to tolerate liquids and absorb carbs during exercise is crucial for endurance events. A well-trained gut maintains consistent energy levels and hydration, likely improving performance. Experiment during training to optimize your race day nutrition strategy.

Shelia Healey

Written by Sheila Kealey; health promotion consultant, nutrition researcher, and health writer. She has worked with researchers at the University of California, San Diego, for over 20 years studying how diet influences health and investigating the most effective strategies to improve lifestyle behaviors like diet and physical activity

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