Whether you’re training for your first 10km or preparing for an ultramarathon, knowing when to fuel can make a big difference to your performance. Carbohydrates are your body’s preferred energy source during endurance exercise, and getting the timing right can help you stay energised from start to finish.
Why do runners need carbohydrates?
When you eat carbohydrates, your body stores them as glycogen in your muscles and liver. During exercise, these stores are broken down to provide energy. Once glycogen levels begin to run low, you may experience the dreaded “wall” – a sudden drop in energy, pace, and concentration.
Replacing some of those carbohydrates during longer runs helps keep your energy levels stable and supports consistent performance.
Do you need carbs on every run?
Not necessarily. The length and intensity of your run determine whether mid-run fuel is needed.
Runs under 60 minutes
Most runners don’t need to consume carbohydrates during shorter runs. Having a balanced meal or snack one to three hours before heading out is usually enough.
Runs between 60 and 90 minutes
Fuel may not be essential, but it can be beneficial if you’re running at a high intensity or training for an event. A sports drink or small energy gel may help maintain your energy levels.
Runs over 90 minutes
This is where carbohydrate intake becomes important. Aim to consume around 30–60g of carbohydrates per hour. Well-trained endurance athletes may tolerate up to 90g per hour when using multiple carbohydrate sources.
How often should you eat during a long run?
Rather than waiting until you’re tired or hungry, fuel consistently throughout your run.
A good rule of thumb is to:
- Start fuelling after the first 30–45 minutes.
- Continue taking in carbohydrates every 20–30 minutes.
- Sip water regularly to aid digestion and stay hydrated.
By fuelling early, you’re topping up your energy before your glycogen stores become depleted.
What are good carbohydrate options?
There are plenty of convenient ways to fuel during a run, including:
- Energy gels
- Chews or gummies
- Sports drinks
- Bananas
- Dried fruit
- Soft energy bars
The best option is one that sits comfortably in your stomach. Every runner is different, so it’s important to practise your race-day nutrition during training rather than trying something new on event day.
Listen to your body
Fuel recommendations provide a helpful guide, but individual needs vary based on your pace, body size, fitness level, and the weather. If you’re preparing for a marathon or another endurance event, consider speaking to a registered dietitian or sports nutritionist to develop a personalised fuelling strategy.
The more you practise your nutrition during training, the more confident and comfortable you’ll feel on race day.