Quick summary:
- ✅ In ultra-running, nutrition is a central strategy: you have to nourish your body as much as you push it.
- ⚡ Recommended intake: 60 to 90 g of carbohydrates/hour, with a mix of sources and good digestive tolerance.
- 🍲 Vary textures and flavors (sweet/salty, liquid/solid) to avoid disgust and to last over time.
Why is nutrition crucial in ultramarathons?
In ultra-distance running (trail running, cycling, long-distance ski touring, etc.), nutrition becomes a true strategy for "energy and digestive survival." It's no longer just about enduring, but about intelligently nourishing your body to sustain effort .
Your body burns thousands of calories and your digestive system is put under considerable strain. Mismanaging your nutrition risks a crash, digestive problems, or simply giving up.
Nutritional goals in ultra-marathons
The number one objective is simple: to maintain a regular intake of carbohydrates , without saturating the stomach.
- Recommended intake : 60 to 90 g of carbohydrates per hour (i.e. 240 to 360 kcal/h).
- Various sources : drinks, bars, gels, salty foods.
- Digestive tolerance : adjust according to your sensitivity and experience.
The challenge of long hours
After 6–8 hours of exertion, appetite decreases , tastes change , and digestion becomes erratic. This isn't a glitch; it's normal. The body goes into "economy" mode, and blood flow is redirected: to the detriment of the digestive system and to the benefit of the muscles.
The keys to holding on
- Vary the textures and flavors : sweet/salty, liquid/solid.
- Include comfort foods, tested during training.
- Don't forget sodium : drinks, soup, crackers, salted mashed potatoes.
| Good idea ✅ | Avoid ❌ |
|---|---|
| Alternate drinks, bars, purees, soup | Eat only gels for 10 hours |
| Introduce salt after 4–5 hours | Consuming only sugary foods → risk of overindulgence |
| Plan to include familiar treats. | Testing a new product on race day |
| Add sodium via crackers, drinks | Ignoring salt loss → possible cramps |
Carbohydrate intake: what does science say?
A study by Pfeiffer (2012) showed that athletes tolerated a glucose + fructose mixture (2:1 ratio) better. This combination allows:
- To increase carbohydrate intake beyond 60 g/h.
- To reduce digestive problems related to sugar alone.
- To improve the total oxidation of ingested carbohydrates.