Before you run
For runs over about an hour, a carbohydrate-focused meal 1–4 hours out, sized to how close it is to the start, helps you start with full tanks instead of running down what you have left from yesterday. See fueling before exercise for timing and meal-size guidance.
During the run
Past about an hour, the question becomes grams of carbohydrate per hour, and running's constant impact makes the gut a bigger factor than it is on a bike. The full breakdown by distance is in how many carbs per hour running. Training for a marathon specifically? Marathon fueling covers race-morning timing and in-race strategy. Building up your long runs? Long-run fueling covers what to practice and when.
After the run
Replenishing carbohydrate and getting some protein in soon after a hard or long run helps you recover, especially heading into back-to-back training days. See fueling after exercise for the details.
Fueling by distance
- 5K–10K: mid-run fueling is rarely relevant; the pre-run meal matters more.
- Half marathon: a gel or two, or an equivalent, is common for most runners at this distance.
- Marathon: this is where a real in-race carbohydrate strategy starts to matter, built and practiced in training long runs, not improvised on race day.
- Ultramarathon and trail: lower relative intensity over many hours, with real food and variety playing a bigger role than gels alone.