The Short Answer
Ultra nutrition is fundamentally different from marathon fueling because duration creates more opportunities for appetite, taste, and tolerance to change. Start the plan you practiced before a large deficit develops, use small familiar portions, and adjust rather than forcing food through escalating symptoms.
What Ultrarunners Actually Eat
| Situation | Priority | Options to Test |
|---|---|---|
| Plan is working | Repeat a tolerated range without chasing a perfect number | Drink mix, gels, rice, sandwiches, bananas, potatoes |
| Taste fatigue | Change flavor or texture while keeping ingredients familiar | Pretzels, crackers, broth, noodles, neutral foods |
| Mild nausea | Reduce effort and portion size; reassess concentration and fluid | Small sips or bland bites already tested in training |
| Overnight | Maintain variety and count caffeine from every source | Warm savory choices plus tolerated carbohydrate |
The Science
Research provides planning ranges rather than a universal absorption ceiling. An ultramarathon nutrition position stand suggests a broad 150–400 kcal per hour range, often including 30–50 g carbohydrate and 5–10 g protein, but those figures need individual testing. Practice the exact foods, concentrations, and portions over a gradual training build; there is no evidence-based number of weeks that guarantees tolerance. Check our best ultra nutrition products guide for specific product recommendations.
What to Practice in Training
Practice food combinations, not just individual products. A gel may work in isolation and fail after hours of sweet drink mix. A sandwich may taste perfect at lunch and feel impossible at 3 AM. Long runs are where you learn your personal order of operations: what works early, what works when you are nauseous, and what still sounds acceptable after taste fatigue sets in.
Build a small menu with categories rather than one perfect plan: liquid carbohydrate, soft bland foods, savory foods, quick carbohydrate, and warm comfort food. That gives you options when the stomach starts negotiating.
Common Fueling Mistakes
- Waiting for a large energy deficit before starting the practiced plan
- Using only sweet products until flavor fatigue makes them unusable
- Forcing food, fluid, or sodium to hit a target despite worsening symptoms
- Trying new foods on race day because they look good at the aid station
Sources
- Tiller, N.B. et al. (2019) — International Society of Sports Nutrition Position Stand: Nutritional Considerations for Single-Stage Ultramarathon Training and Racing. Journal of the International Society of Sports Nutrition, 16, 50.
- Costa, R.J.S. et al. (2017) — "Systematic Review: Exercise-Induced Gastrointestinal Syndrome—Implications for Health and Intestinal Disease." Alimentary Pharmacology & Therapeutics, 46(3), 246–265.