Nutrition in the 24 hours leading up to an endurance event can directly influence an athlete’s performance. While training remains the primary determinant of success, arriving at the starting line with adequate energy stores, proper hydration, and a well-prepared gastrointestinal system can make a significant difference during competition.
Many athletes focus only on what they will consume during the race, but nutritional strategy begins long before the start. The choices made the day before can impact muscle glycogen levels, hydration status, and even gastrointestinal comfort throughout the event.
The Role of Glycogen in Performance
Glycogen is the body's primary carbohydrate reserve and one of the most important energy sources during prolonged, moderate to high-intensity exercise.
During endurance events such as running, cycling, triathlon, and ultramarathons, glycogen stores are gradually depleted. When glycogen levels become too low, athletes may experience a decline in performance, early fatigue, and difficulty maintaining their planned pace.
For this reason, the 24 hours before competition represent an important opportunity to maximize carbohydrate availability and begin the event with elevated energy reserves.
What to Prioritize in the Day Before Nutrition Plan
The primary nutritional focus should be increasing carbohydrate intake. Depending on the duration of the event and the athlete’s individual characteristics, recommendations may range from 7 to 12 g of carbohydrate per kilogram of body weight during the 24 to 48 hours before events lasting longer than 90 minutes.
Some of the main carbohydrate sources include:
• Rice
• Pasta
• Bread
• Potatoes
• Cassava
• Tapioca
• Fruit
• Sports drinks
• Carbohydrate gels
The goal is not simply to eat more food, but to increase the proportion of carbohydrates in the diet in order to enhance muscle glycogen storage.
The Importance of Hydration
There is no effective carbohydrate-loading strategy without adequate hydration.
Each gram of glycogen stored in the body is accompanied by water. This means that the body must be properly hydrated to optimize glycogen storage. It is common for athletes to notice a slight increase in body weight before competition due to glycogen and water storage, which is both expected and desirable.
In addition to water, sodium intake also deserves attention, especially for athletes with high sweat rates or those competing in hot and humid environments.
What to Avoid in the 24 Hours Before Competition
The day before a competition is not the ideal time to experiment with new foods or supplements.
Unfamiliar foods can increase the risk of gastrointestinal discomfort, nausea, abdominal bloating, and digestive disturbances during the event. This is one of the most common mistakes observed among recreational athletes.
It may also be beneficial to temporarily reduce the intake of foods that are very high in fiber, fat, or strong seasonings, particularly for athletes with a history of gastrointestinal issues during prolonged exercise.
Foods that typically deserve special attention include:
• Fried foods
• Very high-fat meals
• Excessive amounts of raw vegetables
• Large portions of legumes
• Highly seasoned or spicy foods
• Alcoholic beverages
The Last Meal Before Bed
A common question is whether dinner on the night before competition should be exceptionally large.
In practice, what matters most is that carbohydrate intake is distributed throughout the day. Concentrating the entire nutritional strategy into a single "huge pasta dinner" does not guarantee maximum glycogen stores. The ideal approach is to maintain a consistent carbohydrate intake across all meals during the 24 hours before the event.
A balanced evening meal may include:
• Pasta with a simple sauce
• Rice with a lean protein source
• Potatoes with chicken or fish
• Bread paired with light protein sources
How This Strategy Impacts Performance
Athletes who begin a race with adequate glycogen stores and proper hydration are better equipped to sustain their target pace, delay fatigue, and optimize the utilization of carbohydrates consumed during exercise.
Furthermore, a well-planned nutritional strategy in the 24 hours before competition reduces the need for last-minute adjustments and contributes to a more predictable and reliable race-day plan.
Practical Application for Endurance Athletes
In the 24 hours leading up to an endurance event, the primary objective should be simple: increase carbohydrate availability, maintain proper hydration, and avoid introducing any new foods.
Athletes should not focus solely on the dinner the night before, but rather on the entire period leading up to the start. Small decisions made throughout the day can determine how the body responds during hours of continuous effort.
A consistent nutritional strategy that has been previously tested during training and adapted to individual needs is one of the best ways to arrive at the starting line prepared to perform at your highest level.
Conclusion
Nutritional preparation for an endurance event begins before the starting gun. The 24 hours leading up to competition represent a strategic window to maximize glycogen stores, ensure proper hydration, and minimize gastrointestinal risks.
By prioritizing carbohydrates, maintaining adequate fluid intake, and relying only on foods that have already been tested during training, athletes increase their chances of starting the event in optimal condition and sustaining performance all the way to the finish line.
