How to Fuel Your Next Race

No matter the distance, race day performance is built on more than just training. The kilometres you log prepare your body, the countless hours training prepare your mind, but it’s your race day nutrition that can determine how well that preparation actually translates when it counts.

At a physiological level, your body relies heavily on glycogen — a stored form of carbohydrate found in your muscles and liver that breaks down into glucose for energy. This is your most efficient fuel source when running at moderate to high intensities. The catch? Glycogen stores are limited. For shorter races, you can often get by on what’s already stored. But as the distance increases, those stores become a limiting factor, and what you consume before and during the race starts to play a much bigger role. This is why fuelling is not just about avoiding fatigue, but about maintaining pace, preserving concentration, and keeping your effort feeling controlled for as long as possible.

One of the most important principles to keep in mind is that race day is not the time to experiment. Your gut adapts to what you regularly eat and drink in training, so anything new introduced too close to an event can increase the risk of discomfort or poor absorption. A good fuelling strategy should feel familiar, repeatable, and predictable.

The final week before your race is about creating a stable foundation. Rather than making dramatic changes, the focus should be on consistency and ensuring that your body has everything it needs to perform. Carbohydrates are especially important during this phase because they are stored as ready to use glycogen. For shorter races, maintaining your normal intake is usually sufficient. However, if you are preparing for an event lasting longer than around 90 minutes, gradually increasing your carbohydrate intake in the final few days can help maximise glycogen stores.

At the same time, overall diet quality still matters. Training, even at reduced taper volumes, can place stress on the immune system, so maintaining a balanced intake of micronutrients is important.

A simple way to approach this week is to focus on:

The goal is to arrive at race day feeling energised, not depleted or heavy.

By the day before your race, most of the work is already done. This is not a time for aggressive fuelling strategies, but rather for reinforcing what you’ve already built.

The focus should shift toward easily digestible, familiar foods that will sit comfortably in your system. While fibre, fat, and protein are all important parts of a normal diet, higher amounts can slow digestion or increase the likelihood of gastrointestinal discomfort during a race. For this reason, many runners naturally reduce these slightly in favour of more carbohydrate-rich options.

Hydration also becomes more intentional here. Instead of trying to “catch up” late, it’s more effective to sip fluids regularly throughout the day to ensure you begin the race well hydrated.

It can help to think of this day as setting the stage. You’re not trying to gain fitness or make last-minute improvements, just making sure nothing gets in the way of the performance you’ve already built.

Short Races (5K to 10K)

In shorter events, performance is driven largely by the energy you already have stored. Because of this, fuelling during the race itself is usually unnecessary, and over-fuelling beforehand can actually leave you feeling heavy or uncomfortable. The priority is to arrive at the start line feeling light, energised, and ready to move.

Most runners will benefit from eating 2 to 4 hours before the race, choosing foods that are high in carbohydrates and easy to digest (low in fibre, fat, and protein). This might look like toast with a spread, a small bowl of oats, or fruit alongside a sports drink. Some runners will also have a small carbohydrate top-up shortly before the race, particularly if there is a longer gap between their last meal and the start time. This can help maintain blood glucose levels without overloading the stomach. During the race itself, hydration is usually minimal and dependent on conditions. In cooler weather, many runners will not need to drink at all, while in warmer environments, small sips of water may be helpful.

Overall, the approach here is simple: fuel enough to feel sharp, but not so much that it slows you down.

Middle Distance (Half Marathon)

The half marathon sits in an interesting space where both stored glycogen and in-race fuelling begin to matter. While many runners can complete the distance without taking on carbohydrates, doing so can help maintain pace and reduce fatigue, particularly in the later stages.

Pre-race nutrition follows a similar structure to shorter events, but with a slightly greater emphasis on carbohydrate availability. Ensuring that glycogen stores are well topped up can make the effort feel more controlled, especially through the second half of the race.

During the race, introducing a small amount of carbohydrate can help sustain performance. This is often in the form of gels, chews, or sports drinks, typically taken once or twice depending on the runner’s pace and total race time. Hydration also becomes more relevant here, particularly in warm conditions where fluid loss through sweat can begin to impact performance.

The key is to start fuelling before fatigue sets in, rather than reacting to it once it arrives.

Long Distance (Marathon and Beyond)

For longer events, fuelling becomes a central part of the race itself rather than something that simply supports it. Even with well-developed glycogen stores, the body will begin to run low on readily available carbohydrates as the race progresses. Without additional intake, this often leads to a significant drop in pace and perceived effort increasing sharply, commonly known as “hitting the wall.” To avoid this, a consistent fuelling strategy is essential.

In the lead-up, carbohydrate intake is typically increased over the final few days to maximise glycogen stores. On race morning, a familiar, carbohydrate-rich meal consumed 2 to 4 hours before the start helps ensure that both liver and muscle glycogen levels are high. During the race, the focus shifts to maintaining a steady supply of energy and fluids:

Rather than thinking of fuelling as occasional refuelling stops, it’s more useful to think of it as a continuous process. Small, consistent inputs help maintain stability and delay the onset of fatigue.

Once the race is over, recovery begins immediately. While it can be tempting to switch off completely, what you eat and drink in the hours following can have a significant impact on how quickly your body recovers.

After running, glycogen stores are depleted and muscle tissue has been placed under stress. The body is particularly receptive to nutrients at this time, making it an ideal window to begin replenishing and repairing.

Carbohydrates help restore glycogen levels, while protein provides the building blocks needed for muscle repair. Fluids, along with electrolytes, help replace what has been lost through sweat.

In practice, this might involve a combination of whole foods and convenient options like recovery drinks, depending on what feels most tolerable post-race.

Even after shorter events, prioritising recovery nutrition can support consistency in training and reduce lingering fatigue.

Fuelling for a race is not a one-size-fits-all approach. It scales with the demands of the event, becoming more important and more structured as distance increases. Short races reward simplicity and restraint. Longer races reward planning and consistency. When done well, fuelling allows your body to do what it has already been trained to do, without unnecessary limitations.