Trail running is unpredictable by nature. Steep climbs, fast descents, and technical sections constantly shift your intensity. Your nutrition strategy should reflect this variability — it needs to be flexible, not static.
When fuelling is executed properly, you:
- sustain consistent energy output
- delay the onset of fatigue
- lower the risk of gastrointestinal (GI) distress
- support faster recovery post-race
Phase 1: Carb loading (24–48h before)
This phase focuses on maximizing glycogen stores, your body’s primary energy source during endurance efforts.
Recommended intake: 8–10 g carbohydrates per kg body weight per day.
→ For a 70 kg athlete: approx. 560–700 g carbs daily
To reach this level efficiently:
- prioritize low-fiber, easy-to-digest foods (white rice, pasta, bread)
- keep fat and protein intake moderate to allow higher carb intake
- include liquid carbohydrates (e.g. isotonic drinks) if appetite is reduced
- spread intake across multiple meals and snacks
Keeping fiber low is important, as excessive fiber increases the likelihood of stomach issues during the race.
Phase 2: Pre-race (2–4h before)
The goal here is to top up glycogen stores while ensuring optimal hydration before the start.
Recommended intake: 1–4 g carbohydrates per kg body weight.
Practical approach:
- choose easily digestible carbohydrate sources
- avoid high fat and high fiber foods
- include fluids with electrolytes to support hydration
Hydration should start well before the gun goes off. Arriving at the start already hydrated is a key performance factor.
Phase 3: Mid-race fuelling
This is where performance is either maintained—or lost. Once glycogen levels drop, performance typically declines quickly, not gradually.
To prevent that, fuelling must match the demands of the effort:
- 60–90 g carbs/hour for moderate intensity
- 90–120 g carbs/hour for high intensity
- 500–600 ml fluids/hour as a baseline
- up to 1–1.5 L/hour in hot conditions
Since glycogen storages are limited, timing is critical. Instead of following a rigid schedule, adapt intake to the course:
- increase carbohydrate intake before climbs
- maintain or slightly reduce carbohydrate intake on descents and flats
- stay proactive—don’t wait until energy drops
A flexible approach helps stabilize energy levels and reduces digestive stress.
Hydration & sodium
Sweating leads to both fluid and sodium loss. Replacing fluids with water alone can dilute sodium levels and impair absorption.
Consequences may include:
- reduced hydration efficiency
- increased cramp risk
- higher likelihood of GI discomfort
Typical sodium intake with 6d Sports Nutrition products:
- 6d Sports & Ultra Gels, Salty Sports Bars, Salty Sports Chews → ~200 mg sodium
- 6d Sports & Ultra Drinks → ~400 mg sodium
- Electrolyte solutions (Hydro/ORS) → ~450–900 mg sodium
Common mistakes
Even experienced athletes often:
- rely only on water
- delay fuelling until it’s too late
- underestimate carbohydrate requirements
- try to fix issues mid-race instead of preventing them
The result is usually the same: sudden energy drops, digestive problems, and performance decline.
The most successful athletes fuel early, stay consistent, and avoid reactive decisions.
Where to start?
You can find a full range of race-day nutrition — gels, drinks, bars, and electrolytes at: https://www.laprimafit.com/
Kočevsko Outdoor Festival athletes can use code KOF for 25% off.
La Primafit is an official partner of Amacx Sports Nutrition, 6d Sports Nutrition, Maurten, Precision Fuel & Hydration, Nomio, Pelotan, 226ERS, and others.
📩 Questions? Contact: grega@laprimafit.com
This is a general guideline, not an individualized nutrition plan. Always test your strategy in training before race day.
