Menu
As endurance athletes push their physical limits, the importance of a well-functioning gastrointestinal (GI) system becomes increasingly clear. Proper nutrition is crucial for sustaining energy levels and performance, but for many athletes, the ability to consume and absorb food and fluids during prolonged exercise is a challenge and in some cases can become a complete disaster (think Paula Radcliffe London Marathon 2005, if you’re too young to remember maybe don’t Google it and just trust me on this). This is where “training the gut” comes into play—a strategy that can enhance performance by reducing gastrointestinal distress and improving nutrient absorption.
Training the gut refers to the process of adapting the gastrointestinal system to better tolerate and process the intake of food and fluids during exercise. This concept is rooted in the understanding that the gut, much like muscles, is adaptable and can be conditioned through specific training practices.
Gastrointestinal issues are a common problem among endurance athletes, with many experiencing symptoms like bloating, nausea, cramping, and diarrhoea during long-distance events. These symptoms can severely impact performance and overall enjoyment for an event. Endurance athletes put so much work into their training and it pains me to think how many people go on to not enjoy their big race day due to their nutrition.
Training the gut can help mitigate these issues by:
All of the above contributes towards higher energy levels, delayed fatigue, and a more consistent pace throughout the event (assuming you’re not like me and you are actually capable of setting and sticking to a pacing plan).
Training the gut isn’t as hard or complicated as many would make out, but it does require a gradual and patient approach.
Gradually Increase Carbohydrate Intake During Training: One of the primary goals of gut training is to increase the amount of carbohydrates that the gut can handle during exercise. This is particularly important because carbohydrates are the main fuel source for endurance activities.
Start with Lower Volumes: Begin by consuming small amounts of carbohydrates during training sessions, such as 20-30 grams per hour. Gradually increase this amount over several weeks, aiming to reach 60-110 grams per hour, depending on the intensity and duration of the exercise.
Use Multiple Transportable Carbohydrates: Carbohydrates like glucose and fructose use different transport pathways in the gut. By combining these in your nutrition plan, you can increase the total amount of carbohydrates absorbed, reducing the risk of GI distress and improving energy availability. There is also evidence that some of the changes that happen whilst training the gut are specific to the types of sugar that are being consumed, so having both helps lead to the adaptions that are going to be required1. Plus once you get up to 60 grams per hour you really need to make sure you’re taking on both glucose and fructose, ideally in a 2:1 or 1:0.8 ratio. Luckily most reputable sports nutrition brands are aware of this so they tend to include a combination of sugars, but always play it safe and check the label.
Practice During Training: It’s essential to replicate race-day conditions in your training sessions. Practice consuming the precise products you plan to use during competition, so your gut becomes accustomed to them.
Regular Intervals: Start consuming carbohydrates and fluids early in your training session, ideally within the first 20-30 minutes, and continue at regular intervals (every 15-20 minutes) throughout the session.
Adapt to Fluid Intake: Fluids are essential for maintaining hydration, but consuming large volumes can be challenging, especially during high-intensity exercise. Gut training can help you better tolerate the intake of fluids, reducing the risk of dehydration without causing bloating or discomfort.
Progressive Hydration Training: Start by drinking small amounts of fluid at regular intervals, and gradually increase the volume as your training progresses.
Training the gut, like any aspect of endurance training, comes with its challenges. However, with the right approach, these can be managed effectively:
Training the gut can be an essential strategy for endurance athletes looking to improve their performance and reduce the risk of gastrointestinal issues during competition. By gradually adapting the gut to handle higher volumes of food and fluids, athletes can enhance nutrient absorption, sustain energy levels, and enjoy a more comfortable, fun race experience. Incorporating gut training into your regular training routine will prepare your body to perform at its best on race day, ensuring that your nutrition strategy is as well-honed as your physical conditioning.
1 Yau, A. M., McLaughlin, J., Maughan, R. J., Gilmore, W. & Evans, G. H. Short-term dietary supplementation with fructose accelerates gastric emptying of a fructose but not a glucose solution. Nutrition 30, 1344-1348, doi:10.1016/j.nut.2014.03.023 (2014).
2 King, A. J. et al. Short-Term Very High Carbohydrate Diet and Gut-Training Have Minor Effects on Gastrointestinal Status and Performance in Highly Trained Endurance Athletes. Nutrients 14, doi:10.3390/nu14091929 (2022).
3 Jeukendrup, A. E. Training the Gut for Athletes. Sports Med 47, 101-110, doi:10.1007/s40279-017-0690-6 (2017).
4 Martinez, I. G., Mika, A. S., Biesiekierski, J. R. & Costa, R. J. S. The Effect of Gut-Training and Feeding-Challenge on Markers of Gastrointestinal Status in Response to Endurance Exercise: A Systematic Literature Review. Sports Med 53, 1175-1200, doi:10.1007/s40279-023-01841-0 (2023).
