Fuelling the Distance: Why Nutrition Becomes the Deciding Factor in Long-Distance Racing

Why Nutrition Becomes the Weak Point on Race Day

Endurance sports often persuade athletes that fitness alone is sufficient. If the training is completed, the long runs logged, and the pacing plan set, then the result should follow. Yet for many runners tackling their first marathon, ultra, or long trail event, it is not their legs or lungs that break down on race day, it is their fueling.

Why Nutrition Matters More the Longer the Race Gets

Nutrition matters in all forms of sports, but in long-distance racing, it becomes particularly decisive. As race duration increases, the margin for error narrows. Small mistakes in fueling or hydration that would be unnoticed in a short event compound over hours, often leading to sudden fatigue, loss of pace, nausea, cramping, or the familiar experience of “hitting the wall.” Understanding how and why the body fuels endurance exercise is therefore not about optimisation or marginal gains; it is about giving yourself the ability to finish strong.

Carbohydrates and Glycogen: The Foundation of Endurance Fueling

At the centre of endurance nutrition is carbohydrate. While the body stores large amounts of energy as fat, it relies heavily on carbohydrate, stored as glycogen in the muscles and liver, to sustain moderate to high-intensity effort. Glycogen stores are typically sufficient to fuel between 90 minutes and three hours of running, depending on the intensity and training status. Once these stores are depleted, pace inevitably drops, regardless of fitness. This is why carbohydrate availability becomes increasingly important the longer a race lasts, and why successful endurance fueling focuses on both starting the race with full glycogen stores and continually replenishing carbohydrates during the event.

The Night Before the Race: Setting Up Glycogen Stores

The process begins the night before the race. The purpose of the pre-race dinner is not indulgence but preparation: maximising glycogen stores while minimising digestive stress. Meals should be familiar, high in carbohydrates, and relatively low in fat and fibre. Foods such as pasta, rice, potatoes, or white bread paired with a small amount of lean protein work well for most athletes. The goal is not to eat until uncomfortable, but to ensure that carbohydrates form the majority of the meal so that muscle and liver glycogen stores are topped up for the following day.

Race Morning Nutrition: Timing and Simplicity Matter

Race morning nutrition serves a similar purpose, but timing becomes critical. Eating two to three hours before the start allows enough time for digestion while still contributing to glycogen availability. A carbohydrate intake of roughly one to two grams per kilogram of bodyweight is a useful guideline, achieved through simple foods such as toast with honey, oats, a banana, or a sports drink for those who struggle with solid food early in the day. As with all aspects of race nutrition, familiarity is key. Race morning is not the time for experimentation.

Fueling During the Race: From Storage to Maintenance

Once the race begins, the emphasis shifts from storage to maintenance. One of the most common mistakes among first-time endurance athletes is waiting until they feel tired or hungry to start fueling. By the time those sensations appear, carbohydrate depletion is already well underway. Evidence consistently shows that endurance performance is improved when carbohydrates are consumed early and regularly during exercise. For events lasting more than two hours, an intake of approximately 60 to 75 grams of carbohydrate per hour provides a reliable balance between energy availability and gastrointestinal tolerance for most athletes.

Consistency Over Quantity: How to Consume Carbohydrates Mid-Race

This intake is best achieved through small, frequent doses rather than large, infrequent ones. Gels, chews, sports drinks, and simple real foods can all play a role, provided they are tested in training. The exact format matters less than consistency. Starting within the first 20 to 30 minutes of the race and continuing at regular intervals helps stabilise blood glucose levels, delays fatigue, and supports both physical and cognitive performance as the race progresses.

Hydration in Endurance Racing: Avoiding Both Extremes

Hydration, while often discussed alongside fueling, requires a more nuanced approach. Fluid needs vary widely depending on environmental conditions, body size, pace, and individual sweat rates. Overhydration can be just as problematic as dehydration, particularly in long events. A general guideline of 400 to 800 millilitres per hour provides a useful starting point, but athletes should aim to drink steadily rather than excessively, guided by both a plan and their perception of thirst.

Electrolytes and Sodium: Supporting Hydration and Performance

Electrolytes, and sodium in particular, play a critical role in effective hydration. Sodium helps the body retain fluid and supports normal nerve and muscle function. During prolonged exercise, especially in warm conditions or for heavy sweaters, sodium losses can be significant. Consuming approximately 300 to 600 milligrams of sodium per hour helps maintain fluid balance and reduces the risk of hyponatremia. This can be achieved through electrolyte drinks, salted gels, or electrolyte supplements, depending on personal preference and tolerance.

Training the Gut: Making Nutrition Race-Ready

Perhaps the most overlooked aspect of endurance nutrition is that it is trainable. The gut adapts to regular carbohydrate intake during exercise, just as muscles adapt to training load. Long training sessions provide the ideal opportunity to practice race nutrition, refine timing, and identify what works best for the individual. Athletes who consistently fuel during training not only improve tolerance but arrive at the start line with confidence, knowing exactly how they will manage the demands of race day.

Nutrition as Part of the Performance System

In long-distance racing, nutrition is not a backup plan; it is part of the performance system. Fitness determines potential, but fueling determines whether that potential can be realised over hours of sustained effort. For first-time endurance athletes, developing a simple, evidence-based nutrition strategy can be the difference between surviving the distance and truly racing it.

Fuel to Finish Strong

If you can fuel early, fuel consistently, and hydrate intelligently, you give yourself the best possible chance to reach the finish line feeling strong, not depleted.pleted.