Preparing for a trail run isn’t just about training hard on the trails. Nutrition, hydration, and supplementation play just as crucial a role as physical preparation. Every race requires a tailored nutritional strategy that can support performance and prevent energy crashes, cramps, or gastrointestinal issues.

In this article, we provide a practical guide on how to best approach nutritional preparation for trail running—from training to recovery, and race-day management.

What is Trail Running?

Trail running is a type of running that is becoming increasingly popular among running enthusiasts. By stepping off paved roads, runners can discover the freedom of running in open, unspoiled spaces, immersed in the beauty of nature.

There is no strict definition of trail running: it can range from a simple run on uneven surfaces—such as gravel paths in parks and natural areas, grassy or earthy forest trails, or fields—to more demanding routes in rugged terrain like rocky mountain paths.

In any case, trail running offers a unique and rewarding experience for those who love running and the outdoors. It’s important to note that competitive trail races follow more specific guidelines that define their characteristics.

These races come in many formats, from short distances for children to ultra-long distances exceeding 160 km. They may include various types of events such as vertical races, stage races, and adventure runs. Competitive trail routes may contain some paved sections, though typically less than 20% of the total distance.

Thanks to this wide variety, each trail runner can choose the experience that best matches their goals and characteristics.

Trail running offers several advantages over road running, including:

1. Greater engagement of stabilizing muscles and lower limbs

2. Reduced joint impact—especially when running on soft surfaces without steep descents

3. The opportunity to enjoy beautiful and scenic views

4. Psychological benefits, such as stress reduction and increased motivation

5. The chance to share the experience with fellow runners and build social connections

6. The thrill of adventure and the challenge of tackling difficult terrain

7. Direct contact with nature, which can foster a deeper appreciation for the environment

Running on natural trails offers a rich and varied experience that combines passion for the sport with immersion in nature and the challenge of pushing personal limits.

Nutrition during training days

When it comes to trail running, training nutrition is essential for achieving your goals. Each runner’s needs vary based on training load, type and purpose of the workout, body composition goals, health, and—especially for younger athletes—growth and development.

The optimal nutrition strategy depends on the type of runner and specific objectives: while some include trail running as part of a weekly training routine without competing, others train with competitive goals in mind.

Here are some key aspects every runner should consider:

  1. Energy: The type, quantity, and timing of food intake are critical to providing fuel for both muscles and the brain. Carbohydrates are the primary energy source, but fats also play an important role—especially during low-intensity or long-distance runs.
  2. Recovery: Trail running, with its intense eccentric muscle load (especially on descents), causes significant muscle stress and fiber damage. Proteins are key in supporting muscle protein synthesis, helping repair and rebuild damaged tissues. They also promote mitochondrial protein synthesis, which allows muscles to produce energy more efficiently and better withstand physical stress—supporting training adaptation.
  3. Energy and health: To function optimally, the body needs a variety of nutrients like vitamins, minerals, antioxidants, fats, and fiber. Fruits, vegetables, nuts, seeds, and healthy fats like omega-3s are all essential to a balanced diet that preserves health while supporting performance.

Whether you are an occasional runner or an elite athlete, a well-planned diet can help you reach your goals and enhance your performance.

Hydration tips

To get the most out of training—and racing proper hydration is crucial. First tip: drink at every main meal and get in the habit of drinking between meals too.

During training, especially due to sweating, you inevitably lose body fluids that must be properly replenished in the hours following exercise. This amount is highly individual and depends not only on environmental factors (like temperature and humidity), but also on exercise adaptation and technical clothing used.

Few people know that the amount of fluid to be replenished post-exercise can be calculated using the following formula: 150% of the body weight lost during exercise, excluding any fluids consumed during the session.

For example, if you lose 1.5 kg during a mountain run and drink 0.5 kg (500 ml) of fluids during the run, the fluids to be replenished are about 1.5 liters (150% of 1 kg, i.e., 1.5 kg – 0.5 kg consumed = 1 kg × 1.5 = 1.5 liters).

In addition to tracking body weight changes, every runner should learn to monitor hydration status using two simple indicators:

1. Urine color: Light yellow or clear urine usually means you are well-hydrated. Dark yellow or orange and strong-smelling urine may signal dehydration.

2. Morning thirst: If you wake up without feeling thirsty, you likely stayed well-hydrated overnight. Waking up thirsty could indicate insufficient fluid intake the day before.

Pre-race nutrition: how to prepare at your best

Every runner has personal preferences regarding food and drinks before a race, and it’s important to respect them—as long as they are aligned with established sports nutrition guidelines. These guidelines can help optimize performance and ensure the body is in peak condition on race day.

For long-distance races, it may be beneficial to do a “carbohydrate loading” phase to maximize energy stores and enhance performance. However, it is essential to consult a qualified sports dietitian or nutritionist to achieve the best results and personalize your nutrition strategy based on your individual needs.

On race day, breakfast can significantly influence the outcome of your performance: many trail runners prefer a light and easily digestible breakfast to avoid gastrointestinal problems during the event. However, if the race will be run at a slow pace—perhaps with long walking stretches especially at the beginning—and it is going to be long, a more substantial breakfast might be tolerated to provide more energy.

In general, the pre-race breakfast should be rich in carbohydrates, the primary energy source for muscles during physical exertion. A small amount of protein may help prevent hunger and maintain satiety during the run, without overloading the stomach. To minimize gastrointestinal discomfort and digestive issues, it’s advisable to limit fat intake and avoid foods that are high in dietary fiber.

Below are some commonly used pre-race breakfast examples, possibly accompanied by a warm and energetic drink such as sweetened tea with honey or sugar:

• Porridge with oat flakes and rice milk

• Toasted white bread with butter and jam or honey

• Rice cakes with peanut butter

• Toast with ham

• A plate of pasta or rice with light sauces

If solid foods are not well tolerated before the race—or if nerves are running high—a smoothie made with rice milk, maltodextrins, and protein powder can be a good liquid source of carbohydrates and protein.

In any case, it’s crucial to listen to your body and choose familiar, well-tolerated foods to avoid gastrointestinal problems during the race.

Nutrition and hydration during the race: which strategies to use

Energy needs and food preferences vary depending on the individual and the type of race:

  • For runs lasting less than 1.5–2 hours, it’s not strictly necessary to consume carbohydrates during exercise if starting with well-stocked glycogen reserves, although small amounts can still be helpful to ensure a steady energy supply.
  • For trail races lasting more than 2 hours, it’s essential to plan personalized nutritional strategies. The higher the running pace, the more important it is to focus on easily digestible and fast-absorbing energy sources, such as the carbohydrates found in Cetilar® gels and the Energy Race Bar, or those in Race Carb and Ultrarace Carb blends—also available with caffeine for a synergistic effect. Supplements for trail running must be effective, palatable, and practical. That’s why Cetilar® offers single-dose gel formats and carbohydrate blends in convenient sachets that are easy to carry and dissolve in water during the run.

For longer events and at slower paces, solid foods—not just supplements—can also be consumed, especially at planned aid stations and base camps.

In ultra-endurance races, it’s important to consider the phenomenon of flavor fatigue, where athletes lose interest in or tolerance for certain flavors if consumed for too long. This occurs particularly with sweet-tasting supplements, which may become unpalatable in the later stages of an ultra-trail.

Therefore, having a variety of food types and flavors is helpful to meet the runner’s needs throughout the entire race.

The sports supplement market is already adapting to this trend, innovating with new flavors and unique combinations. An interesting example is the Balance Race Bar Cheese+Pear, which combines the savory taste of cheese with the sweetness of pear.

Proper hydration during the race is also crucial for every trail runner. Electrolyte replacement should especially be considered in hot and humid conditions or for long distances. In Ultra Trail races, it’s relatively common to experience gastrointestinal problems like vomiting and diarrhea, which can compromise not only performance but even the ability to finish the race—something that is already a major challenge in this type of event.

The key is to find what works best for each individual athlete in various conditions by testing every possible solution during training, before implementing it on race day. Although it's difficult to replicate race-day conditions exactly, training sessions provide a good testing ground to refine the nutrition and supplementation strategy best suited to the athlete. To avoid jeopardizing months of preparation, the rule is: never use anything in a race that hasn’t been tested in training first.

Post-race recovery: what to do?

After an intense training session or a race, it’s essential to implement proper nutritional strategies to promote optimal recovery.

Here are the three golden rules:

  1. Replenish muscle glycogen stores: carbohydrates are the primary energy source for muscles and must be replenished after exertion to avoid depleting glycogen reserves. For rapid replenishment—especially important when another training session is planned soon after, possibly on the same day as in double sessions—high-glycemic index carbs are recommended. This helps ensure that muscles are ready for the next effort.
  2. Repair the muscles: proteins are essential to repair and rebuild muscle tissue that has been put under strain during trail running. To maximize muscle protein synthesis, high-biological-value proteins rich in essential amino acids are recommended. It is therefore crucial to consume an adequate amount of protein in the right combination with carbohydrates—as found in products like Recovery Pro.
  3. Rehydrate: it is important to replace the fluids and electrolytes lost during training or competition to prevent dehydration and support full recovery.bDrinking plain water without minerals is not effective for hydration during or after physical activity, as electrolytes play a vital role in maintaining fluid balance. Electrolytes like sodium, potassium, chloride, and magnesium are essential for proper muscle and nervous system function. When needed, electrolyte supplements are helpful, available in single-dose sachets or sticks to dissolve in water—for example, Hydrate Fast.

After completing a trail race, if there are no other short-term events coming up (as in stage races), it’s advisable to follow a more flexible nutrition plan, perhaps opting for a carb- and protein-rich pizza, accompanied by a low-alcohol beer.

According to some studies, a beer with low alcohol content (around 3–4%) may be acceptable after a race, as it does not appear to significantly hinder rehydration or muscle recovery. However, it’s important to note that alcohol can have different effects from person to person, and moderation is always the best choice.

Here are some examples of recovery meals:

• Fruit smoothie with milk and protein powder

• Greek yogurt with granola and fresh fruit

• Tuna salad with quinoa, cherry tomatoes, and basil

• Sandwich with ham, mozzarella, tomatoes, and lettuce

• Pizza and beer or pizza and Coca-Cola

Other nutritional tips

Remember to plan your nutrition and supplementation strategy for the race in advance, taking into account your specific needs and the expected conditions during the event.

The best strategy is one that can adapt to the ever-changing conditions of each race—such as weather or actual race duration—and to differences among various events, like available food and drink at aid stations or the elevation profile of the course.

A qualified sports dietitian or nutritionist can be a valuable resource in developing a personalized nutrition, supplementation, and hydration plan tailored to your needs.

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Bibliography

Costa RJS, Knechtle B, Tarnopolsky M, Hoffman MD. Nutrition for Ultramarathon Running: Trail, Track, and Road. Int J Sport Nutr Exerc Metab. 2019 Mar 1;29(2):130-140.

Article by Dr. Alessandro Bonuccelli – Sports and Clinical Dietitian