What are the benefits of gut training for runners?

Are you a runner preparing to tackle an event lasting more than 2.5 hours, facing the challenges of high-intensity racing or running in the heat? Do you find it difficult to consume the necessary carbohydrates for fueling races, or struggle with gut issues when trying to take in fluid and food while running? If so, it's time to explore gut training! Gut training improves stomach emptying, absorption and relieves discomforts like nausea and bloating. Unlock peak performance and faster recovery by optimising nutrient delivery from your gut to your muscles. Read on to discover more about the benefits, strategies and get started on your path to a well-trained gut!

Why should I do gut training?

Runners often face gut issues and inadequate fuelling during races. But research shows that higher carbohydrate intake enhances finish times for endurance athletes. To optimise performance, it's vital to support your gut in tolerating and absorbing essential nutrition. That's where gut training comes in, bridging the gap to success.

How does it work?

Gut training can:

Improve carbohydrate absorption: Through gut training, you can increase the transport of carbohydrates from your gut into your bloodstream. This means your body can absorb more fuel, leading to enhanced delivery of carbohydrates to your muscles during exercise, which can improve performance.

Increase rate of stomach emptying: Gut training improves the speed at which your stomach empties during exercise. This reduces symptoms like nausea, bloating and fullness, making it easier to maintain fueling and enjoy running.

What does gut training involve?

Gut training involves purposefully conditioning your digestive system by gradually increasing nutrient and fluid intake in terms of volume, frequency, and variety. Strategies targeting stomach comfort and emptying work faster than those focusing on gut absorption. Options for gut training include:

1. Train with relatively large volumes of fluid: This helps "train the stomach" by gradually increasing the amount of fluid you consume during training sessions.
2. Train immediately after a meal: Conducting training sessions soon after a meal mimics the challenge of digesting and absorbing nutrients while running.
3. Train with relatively high carbohydrate intake during exercise: By consuming higher amounts of carbohydrates during your runs, you condition your gut to effectively absorb and utilise carbs for energy.
4. Simulation of your race nutrition plan: This allows your gut to adapt to the specific foods, fluids, and timing you will use on race day.
5. Increasing carbohydrate content of your diet: Adjusting your overall diet to include higher carbohydrate content helps support gut adaptation and improved carbohydrate absorption.

Depending on your goals, you will need to dedicate a minimum of 1-2 weeks to gut training, performed on at least 2 days per week. Athletes with poor food and fluid tolerance or more severe exercise-associated gut symptoms may require up to 12 weeks of gut training. Relying solely on fueling during long Sunday runs may not be sufficient for maximising gut absorption and comfort. Experiment with various foods and drinks, including high volumes of fluid, concentrated or less concentrated fluids, bars, race foods, gels and fructose.

What is the evidence in humans that gut training works?

In a study involving 18 recreational runners of varying abilities, the effects of gut training were investigated. The runners completed an initial gut challenge of 2 hours of running at moderate intensity whilst consuming 90 grams of carbohydrates per hour, followed by a 1-hour performance test. The runners were then divided into two groups: one trained whilst consuming high amounts of carbohydrates during their 1-hour exercise sessions, while the other group did not consume any carbohydrates during training. This training was conducted for 5 days a week over a two-week period, with some runners having energy gels every 20 minutes and others not consuming any gels.

The results of this study revealed significant improvements in the runners who trained with high carbohydrates. During the follow-up challenge, they experienced reduced stomach discomfort, better absorption of carbohydrates and an average improvement of 600 metres in the 1-hour performance test. Interestingly, although the discomfort was reduced, the high carbohydrate group did not find it easier to consume carbohydrates, likely due to the challenges of frequent fueling.

Another study focused on mountain marathon runners who engaged in gut training for 3-4 weeks, at least 2 days per week. The findings indicated a trend for runners who consumed 120 grams of carbohydrates per hour to perform better than those who consumed fewer carbs. Additionally, the group with higher carbohydrate intake demonstrated improved recovery in terms of muscle function and aerobic capacity.

Further supporting the efficacy of gut training, a systematic review of eight studies highlighted that a 2-week repetitive carbohydrate feeding protocol decreased gut discomfort by an average of 26-47% and through repeated fluid consumption. Gut-training exercises and feeding challenges before or during exercise also contributed to decreased discomfort in the upper and lower digestive system and improved carbohydrate absorption. Future studies utilising specialised equipment will refine gut training guidelines.

How do I incorporate gut training into my schedule?

To incorporate gut training effectively into your schedule, follow these steps:

1. Assess regular training diet: Evaluate your diet to support gut adaptation to high carbohydrate fueling, ensuring sufficient daily carbohydrate intake to prepare your gut for processing and absorbing greater carbohydrate loads during exercise.
2. Assess gut tolerance: Experiment with fueling levels during runs to find what feels comfortable and minimises gut symptoms, shaping your gut training approach.
3. Consider fueling goals: Evaluate desired fuel levels for your target event. Take into account your fitness status, as recreational athletes may face more challenges with exercise-associated gut symptoms than elite athletes.
4. Strategic planning: Select optimal weeks in your race calendar for dedicated gut training sessions, avoiding the final tapering period to allow ample time for effective training.
5. Simulate race fueling: Replicate race-day fueling during gut training, practicing timing, food and fluid choices and overall approach to adapt your gut to race conditions.
6. Monitor progress: Use available resources, such as a log book, training diary or app, to track and analyse gut training progress over time.

Summary

Unleash your running potential with gut training! Conquer discomfort, optimize nutrient absorption and fuel for peak performance. Increase nutrient intake, simulate race-day nutrition and plan strategically for a well-trained gut. Bid farewell to stomach troubles and embrace unparalleled running achievements. Ignite your potential through the transformative journey of gut training!

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References

Jeukendrup 2017, 'Training the gut for athletes', Sports Medicine, vol. 47, s 1, S101-S110.

Martinez et al 2023, 'The effect of gut-training and feeding-challenge on markers of gastrointestinal status in response to endurance exercise: A systematic literature review, Sports Medicine, vol. 53, pp. 1175-1200.

Miall et al 2018, 'Two weeks of repetitive gut-challenge reduce exercise-associated gastrointestinal symptoms and malabsorption', Scand J Med Sci Sports, 28(2):630-640.

Viribay et al 2020, 'Effects of 120 g/h of Carbohydrates Intake during a Mountain Marathon on Exercise-Induced Muscle Damage in Elite Runners', Nutrients, 12(5), 1367; https://doi.org/10.3390/nu12051367.