Marathon training builds the engine, but marathon fuelling determines how well that engine performs on race day. Even the most well-prepared runners can struggle if energy intake is mistimed, insufficient or unfamiliar.

With 26.2 miles placing sustained demands on glycogen stores, hydration and digestion, fuelling isn’t an optional extra. It’s a core part of marathon performance, just as important as pacing or footwear.

This guide explains how to fuel before, during and after a marathon, and how to practise your strategy in training so race day holds no surprises.

The body stores carbohydrate as glycogen in the muscles and liver, but those stores are limited. For most runners, glycogen depletion begins to affect performance after around 90 minutes of running.

When glycogen runs low, pace drops, fatigue increases, and concentration suffers due to the experience of “hitting the wall”. Effective fuelling helps maintain carbohydrate availability, stabilise energy levels and support hydration and electrolyte balance, allowing you to sustain effort for longer and finish stronger.

In the final 48 to 72 hours before race day, marathon training volume will decrease while carbohydrate intake increases. This allows for glycogen stores to fully replenish, ensuring you start the race with maximum available energy. Here, you should focus on easily digestible carbohydrates while slightly reducing fibre and fat to keep digestion smooth. 

To make sure digestion is not uncomfortable, it is important to use familiar products that you have used before, which is why we recommend using products in your training plan. For example, when training with long runs, you can try using energy gels to acclimatise your body to the feeling and the energy boost.

Using familiar energy products during race week can help increase carbohydrate intake without overloading meals. Veloforte’s running nutrition range fits naturally into this phase, providing real-food energy you’ve already tested in training.

Once the race begins, it is important to have a plan for keeping energy levels high and fuelling the body to keep going. For most marathon runners, aiming for 30–60g of carbohydrate per hour is a sensible starting point, depending on body size, pace and gut tolerance. Rather than waiting for fatigue to set in, fuelling should begin early, typically within the first 30–40 minutes, and continue at regular intervals. This approach helps maintain stable blood glucose levels and reduces the likelihood of late-race energy crashes.

To reach the carbohydrates you need to fuel your run, carrying products like energy chews is essential in keeping your energy high when it's needed most. The energy chews from Veloforte are not only available in tasty flavours but are also incredibly easy to consume while running.

An effective in-race fuelling strategy typically involves:

• Small, frequent carbohydrate doses

• Starting before fatigue appears

• Sticking to a pre-practised schedule

Whilst ingesting carbohydrates is critical, hydration is equally important to ensure you can go the distance. Do not drink excessive amounts, as this can dilute electrolytes and cause discomfort. Understanding when you usually need to drink water is crucial to learn as part of your training. Introducing electrolytes into your drinking stops can help replace those lost through sweating, keeping energy levels high.

Crossing the finish line does not mean that fueling is done, as it is incredibly important to make sure you are giving your body the right treatment to recover properly. The first 30–60 minutes after a marathon is a key window for replenishing glycogen and supporting muscle repair. Combining carbohydrates with protein helps kick-start recovery, reduce muscle soreness and speed your return to normal training.

When appetite is low but nutritional needs are high, simple, easily digestible recovery options can make a real difference.

Many marathon fuelling problems come from good intentions paired with poor execution. Common mistakes include:

• Under-fuelling due to fear of stomach issues

• Using unfamiliar products on race day

• Waiting until fatigue hits before fuelling

The most successful marathon runners keep things calm and consistent, trusting the strategy they’ve already practised in training.