How to properly prepare your nutrition for an autumn trail race?

Running a trail race in autumn offers a unique experience: vibrant landscapes and welcome coolness after the summer heat, but also changeable weather, muddy terrain, and longer nights. While the body is prepared through training, success in such a race depends above all on the refuelling strategy.

In this article, we will explore in detail how to prepare a nutritional plan for an autumn trail race, drawing on the season’s major events such as the Festival des Templiers, the legendary SaintéLyon, and the Hivernal des Templiers. We will look at how to use the Nutribay calculator, which products to prioritize, and how to adapt your strategy to cool, humid conditions.

1. Why does autumn change everything in trail running?

Running a trail race in autumn is nothing like running a summer trail race. Cooler temperatures may seem like an advantage, since they reduce the risk of dehydration caused by the summer heat. However, they introduce another challenge: the body may sometimes need to expend more energy to maintain its core temperature, particularly during early-morning starts or nighttime races. Added to this are the specific terrain conditions: humidity, rain, and fallen leaves make the trails more unstable and technical. Every footfall requires greater vigilance, which tires the muscles more quickly. As a result, the runner expends more energy, sometimes without even realizing it.

Source: https://www.saintelyon.com/

Major autumn events such as the Festival des Templiers in October, the legendary SaintéLyon in December, and the Hivernal des Templiers are perfect examples of these demanding conditions. Every year, these races bring together thousands of enthusiasts who come to challenge themselves not only against the distance and elevation gain, but also against the cold, humidity, and the resulting nutritional demands.

2. Building your nutrition strategy: the scientific intake

To properly prepare for an autumn trail, it is essential to understand the body's physiological needs during activity. During prolonged exercise, glucose remains the primary fuel. Scientific research shows that an intake of between 60 and 90 grams of carbohydrates per hour is optimal for supporting performance and avoiding the infamous “energy wall.” But not all carbohydrates are equal. Combining glucose and fructose helps diversify absorption pathways and maximize energy intake without overloading the digestive system.

Hydration is also key to success. Even in cold weather, the body loses water through sweat and breathing. On average, 0.5 to 1 L of drink per hour is recommended, adjusted according to the temperature, duration, and intensity of the run, as well as your sweat rate. This is where the Nutribay calculator becomes an essential ally. 

The Nutribay calculator is a valuable tool for determining your energy, carbohydrate, and hydration needs based on:

• The planned duration of the effort.

• Your weight and running intensity.

• Weather conditions.

In just a few clicks, you get a precise plan: the number of gels, bars, and drinks you need. Ideal for preparing your personal nutrition supplies or anticipating what you will need to collect at the official aid stations.

3. Which products should you choose in autumn?

Choosing energy products is far from trivial, especially when temperatures drop and humidity sets in. Energy bars, for example, should remain easy to chew, even when they have cooled slightly. Textures that are too hard or sticky quickly become difficult to manage after several hours of running. Soft bars made with fruit or tender oat flakes are therefore ideal for maintaining an enjoyable, easy-to-digest intake.

Copyright: colin-olivero-production

Gels also play a central role in a nutrition strategy. In autumn, it is preferable to choose gels that are easy to digest, low in acidity, and easy to swallow. Alternating flavors helps prevent the queasiness that always threatens after several hours of repeated intake. Some caffeine-enriched gels become valuable allies toward the end of the race, particularly during the SaintéLyon, as dawn approaches and alertness threatens to fade.

Finally, isotonic drinks should be selected carefully. In cold weather, flavors that are too sweet or too intense quickly become unpleasant. Light fruit flavors, such as lemon or berries, are easier to drink. These drinks not only provide carbohydrates, but also replace lost electrolytes, which are essential for preventing cramps and muscle failure.

4. Adapting your plan to legendary French trails

Each autumn trail has its own requirements, and adapting your nutrition to the chosen race is essential.

4.1. The Festival des Templiers (October)

The Festival des Templiers, for example, takes place in October in Millau and offers distances ranging from 17 to 100 kilometers. The climate remains mild, but the humidity and significant elevation gain make energy expenditure substantial. In this context, it is advisable to alternate gels and bars approximately every hour, while making sure to drink isotonic fluids regularly. Official aid stations allow you to vary your intake with fruit or soup, but most of your nutrition should come from what you have tested and prepared in advance.

Duration: 6 to 15 hours depending on the distance.
Conditions: mild but often humid climate, significant elevation gain.

Sample plan:

• 1 gel every 45 minutes.

• 1 bar every 2 hours.

• Continuous isotonic drink (500 ml/h).

• Make use of the official aid stations for variety (bananas, soup).

4.2. La SaintéLyon (December)

The SaintéLyon, on the other hand, presents a completely different challenge. A midnight start, temperatures often close to freezing, and omnipresent mud make the conditions grueling. Here, the nutrition strategy must include not only a regular carbohydrate intake but also suitable logistics. Bars and gels must be kept warm, close to the body, to prevent them from hardening. The use of caffeinated gels is especially appropriate after four or five hours of exertion, when fatigue sets in and alertness declines.

Duration: 7h to 12h.
Conditions: midnight start, cold (0 to 5°C), mud.

Sample plan:

• Alternate a gel and a bar every 45 minutes.

• Hot drink if possible (soup at aid stations).

• Plan to have caffeinated gels after 4–5 hours of racing (between 4 a.m. and 6 a.m.).

• Plan the logistics carefully: keep bars/gels close to your body to prevent them from hardening.

4.3. l’Hivernal des Templiers (December)

Finally, l’Hivernal des Templiers offers a shorter but often more intense format. Weather conditions, which can sometimes be freezing, require extra vigilance regarding hydration. Easily digestible gels form the basis of an effective nutrition plan, accompanied by an isotonic drink consumed continuously. Introducing a soft bar halfway through the race helps vary textures and maintain optimal digestive comfort.

Duration: 2h30 to 6h.
Conditions: wet and cold, intense effort.

Sample plan:

• Easily digestible gels every 40–50 minutes.

• Continuous isotonic drink intake.

• A soft bar midway through the race to break the monotony.

5. Practical tips for optimizing your fueling

Beyond the numbers and products, a few practical principles make a difference on race day. The first is simple: never try a new product on race day. Every gel, bar, and drink should have been tested during training to ensure good digestive tolerance. It is also important to vary textures and flavors to avoid flavor fatigue, which can quickly eliminate the desire to eat.

Source: https://www.saintelyon.com/
Copyright: Gilles Reboisson

Logistics also play a crucial role. Gels should be placed in the front pockets of your vest so they can be accessed without wasting time. Bars can be pre-cut into small pieces to make them easier to consume uphill or downhill. Soft flasks, meanwhile, make it easy to measure your isotonic drink and adapt it to the race conditions. In cold weather, it is recommended to keep your energy intake close to your body to limit the effects of hardening or freezing. Finally, you should not overlook the reality of the terrain: learning to listen to your body and adjust your plan if nausea appears or you feel empty remains the best guarantee of completing your race successfully.

6. Concrete example of a nutrition plan (SaintéLyon – 10-hour race)

7. Conclusion: autumn, a demanding playground

Taking part in an autumn trail race means taking on a challenge where nutrition plays a central role. Major events such as the Templiers, the SaintéLyon, or the Hivernal remind us that a well-thought-out strategy can make the difference between enduring a race and having a successful experience.

Thanks to the Nutribay calculator, you can anticipate your precise needs and select the right products: easy-to-chew bars, digestible gels, and isotonic drinks that are enjoyable even in cold weather.

In autumn, more than ever, prepare your fueling carefully. Your body will thank you, and you’ll fully enjoy the magic of these extraordinary races.