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Ultra Trail nutrition

As ultra runners, we know that there are moments when low energy levels hit hard. It can happen for various reasons like starting too aggressively, not taking in enough nutrition and hydration, dealing with gastrointestinal discomfort, or simply enduring the duration of the race. Surprisingly, well-trained runners are even more prone to experiencing low energy availability, because their race intensity is higher. That's why it's absolutely crucial for us to delve into race nutrition and grasp its role in achieving peak performance during those ultra-distance events we love so much.

We need to go beyond seeing nutrition as consuming calories; we need to understand how our pacing, hydration, environmental conditions, and even the nutrition we consume before the event all play a part in optimizing our race nutrition. It's about making informed choices and steering clear of fads or quick-fix solutions. By understanding these interconnected factors, we can make smarter decisions about what we fuel our bodies with, avoiding the pitfalls of falling into trends. This knowledge empowers us to take charge of our nutrition, allowing us to fuel ourselves more effectively on race day.

Ultra-trail running is distinguished by its significant energy requirements, leading athletes to encounter low energy availability at various stages during a race. The extent of these energetic demands varies based on running pacing and intensity (rate of energy requirements and the utilization of carbohydrates versus fats). It is crucial to recognize that, despite employing a deliberate fuelling strategy, even the most trained runners can barely meet the energy demands of a race, and that gastrointestinal discomfort affects the majority of athletes and cannot always be avoided (Stuempfle & Hoffman, 2015).

Fat vs Carbohydrate oxydation in relation to intensity
Fat vs Carbohydrate oxydation in relation to intensity

The performance of athletes is significantly impacted by low energy levels. Therefore, to enhance race performance, it is crucial to maintain energy availability. This can be achieved by improving the muscle's ability to store glycogen, incorporating pre-race carbohydrate loading, and enhancing race nutrition. In a recent study, Dr. Jeukendrup (2017) presents a comprehensive overview of "train the gut" techniques and the corresponding adaptations.

Ways to train the gut for long distance endurance
Train the gut method

To improve your capacity to maintain optimal energy availability and to help you practice your nutrition intake, we have identified essential practices that you can implement into your weekly training:

Carb Loading:

Carbohydrate loading, a well-known practice, involves increasing carbohydrate intake before an endurance event. By deliberately boosting muscle glycogen stores, runners can enhance their energy availability during the race. While this technique has been found particularly beneficial for male runners, female runners can still experience benefits, although to a lesser extent (Tarnopolsky et al., 2001).

Embrace Extended Duration Exercise:

Long-duration exercise serves as a vital component in preparing for ultra-distance running. It offers numerous advantages, such as increasing mitochondrial density within the muscles. This increase allows for greater carbohydrate storage capacity, ensuring a steady supply of energy during the race (Lundby & Jacobs, 2016). Additionally, extended duration exercise provides an opportunity for athletes to practice and refine their event-specific nutrition strategies.

Experiment with Running Nutrition Products:

The market offers a wide range of race nutrition products, including sports drinks, gels, lollies, and bars. It is important to experiment with different brands, flavours, and types of products during your training. This trial-and-error process will help you determine which products work best for you, providing the optimal combination of taste, digestion, and energy replenishment.

Nutrition Practice, Train Your Fueling Routine:

Practicing nutrition is just as important as training your body. Establishing a routine for nutrition practice will help you optimize your energy intake. Begin by assessing your current carbohydrate consumption and gradually increase your intake. Beyond 60 grams of carbohydrates per hour, consider incorporating more fructose and aim to reach up to 90 grams per hour (60gr glucose – 30gr fructose). This approach aims to improve your comfort while running with a full stomach, enhance gastric emptying, and maximize carbohydrate absorption through intestinal sugar transport (Jeukendrup, 2017).

Fuel Up with a Hearty Breakfast:

Before your training runs, start your day with a substantial breakfast. This will allow you to experience running with a full belly, simulating race conditions. Experiment with different foods and find the options that provide sustained energy without causing discomfort or gastrointestinal issues.

Hydration: A Key to Success:

Proper hydration is vital for maintaining optimal performance and preventing potential health risks. Throughout your training, closely monitor your hydration levels and fluid losses. Measure your weight before and after runs and keep track of your thirst levels. Dehydration and hyponatremia (excessive water intake leading to low sodium levels) can significantly impact your health and performance (Hoffman et al., 2013). Strive to find a balance and ensure you are adequately hydrated without over-hydrating.


To excel in ultra-distance races, optimizing energy availability is crucial. By incorporating practices such as carb loading, extended duration exercise, experimenting with nutrition products, practicing nutrition, consuming a substantial breakfast, and maintaining proper hydration, you can enhance your performance and increase your chances of success. Embrace these strategies and embark on your ultra-distance running journey with confidence, knowing that you have fortified your endurance and energy levels for the challenges ahead.

Seek Expert Advice from a Sports Dietitian:

For personalized and expert advice on endurance nutrition, we highly recommend reaching out to a sports dietitian who specializes in endurance sports. They possess the knowledge and expertise to tailor nutrition strategies to your specific needs. If you require recommendations for trusted sports dietitians, please feel free to message us.

Expand Your Endurance Nutrition Knowledge:

If you're eager to deepen your understanding of endurance nutrition, we have a fantastic podcast recommendation for you. Check out "The Long Munch" podcast at This podcast delves into valuable insights, tips, and discussions surrounding nutrition for endurance athletes.

By Sidney Willis,

Head Coach of Hungry Runner


Jeukendrup, A.E. 2017, 'Training the Gut for Athletes', Sports medicine (Auckland); Sports Med, vol. 47, pp. 101-10.

Lundby, C. & Jacobs, R.A. 2016, 'Adaptations of skeletal muscle mitochondria to exercise training', Experimental physiology; Exp Physiol, vol. 101, no. 1, pp. 17-22.

Stuempfle, K.J. & Hoffman, M.D. 2015, 'Gastrointestinal distress is common during a 161-km ultramarathon', Journal of sports sciences; J Sports Sci, vol. 33, no. 17, pp. 1814-21.

Tarnopolsky, M.A., Zawada, C., Richmond, L.B., Carter, S., Shearer, J., Graham, T. & Phillips, S.M. 2001, 'Gender differences in carbohydrate loading are related to energy intake', Journal of applied physiology; J Appl Physiol (1985), vol. 91, no. 1, pp. 225-30.


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