What Do Ultrarunners Eat During a Race?

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

The Science

Our default of about 50 g an hour sits between two ranges that are often quoted without anyone explaining that they answer different questions.

• Practical ultra range, 30–50 g carbohydrate per hour. The ISSN position stand on single-stage ultra-marathon suggests a broad 150–400 kcal per hour, often including 30–50 g carbohydrate and 5–10 g protein. These are single-stage ultra recommendations, not measurements proving what most runners tolerate in every multiday format.
• Endurance guideline range, 60–90 g carbohydrate per hour. The ACSM, Academy of Nutrition and Dietetics, and Dietitians of Canada joint position stand puts intake at roughly 60 g per hour for exercise up to about 2.5 hours and up to 90 g per hour beyond that, using multiple transportable carbohydrates such as glucose–fructose mixes. Those higher rates come from a trained gut and from products designed for them.

Start at 50 g an hour and move up only after training at the higher rate. The higher figure assumes deliberate gut training and a carbohydrate source built for high intake rates, and it is usually quoted from higher-intensity endurance research rather than from multiday events. If you see 90 g per hour on a product label or in a race guide, read it as the upper end for a trained gut, not a default; the ISSN calls it likely unrealistic in races longer than about six hours. Practice the exact foods, concentrations, and portions over a gradual training build; our gut-training guide uses six weeks. The running calorie calculator turns an hourly target into gels, drink and real food. 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