Race-Day Fueling — The Plan, Not the Improvisation

By Runsense · Reviewed by Raphael Crawford-Marks, Founder · Last reviewed June 9, 2026

Race day is not the day to improvise your nutrition. A simple, rehearsed plan — a familiar pre-race meal, a fueling rate you've practiced, and a hydration approach you trust — protects the fitness you spent months building. This is general guidance; the golden rule running through all of it is "nothing new on race day."

The pre-race meal

Eat a carbohydrate-rich, familiar meal 1 to 4 hours before the start — on the order of 1 to 4 g of carbohydrate per kg of body weight, scaled to how long before the gun you eat (more if it's 4 hours out, less if it's an hour)1. Keep it low in fat and fiber to avoid GI trouble, and keep it familiar — race morning is no time for a new breakfast.

During the race — match intake to duration

Use the same carbohydrate rates you practiced in training, scaled to how long you'll be out there (see carbs during exercise). For anything longer than about 90 minutes, take carbohydrate steadily from early on rather than waiting until you feel empty — once you've bonked, it's too late to catch up1.

Hydration on race day

Drink to thirst, and know where the aid stations are so you can plan when to take fluid and fuel (see hydration and electrolytes). Don't over-drink "to be safe" — that carries its own risk. Practice drinking on the move in training so it's second nature.

This is not the same as carbo-loading

Carbo-loading — deliberately topping up muscle glycogen over the 1 to 3 days before a long race — is a separate strategy (see carb loading). Race-day fueling is what you eat that morning and take during the race. For long events you may do both; they work together.

Rehearse everything

The single most important rule is to practice your exact race-day fueling and hydration in training — especially on long runs at race effort — so race day is a repeat of something that already worked, not an experiment. That rehearsal is also how you train your gut to tolerate the plan (see gut training).

Sources

  1. Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine Joint Position Statement. Nutrition and Athletic Performance. Medicine & Science in Sports & Exercise 48(3):543-568 (2016). (Joint AND/DC/ACSM position stand on nutrition and athletic performance) ↩

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