Nutrition Plan for Endurance Racing: Fuelling for Success

Carbohydrates are the primary energy source for endurance athletes, providing the necessary fuel for sustained physical activity. These carbs are stored in the body in the form of glycogen—primarily in the muscles and liver. During exercise, glycogen is broken down into glucose to fuel muscle contractions. However, glycogen stores are finite, and once depleted, performance can decline rapidly.
A balanced diet rich in carbohydrates helps maximize glycogen storage, providing endurance athletes with the energy needed for long-distance events like marathons or triathlons. Incorporating complex carbs like whole grains, fruits, and vegetables ensures that glycogen stores are adequately replenished in the lead-up to a race​.

The Athlete’s Wall, or "hitting the wall," is a common phenomenon experienced during endurance events when glycogen stores are exhausted. At this point, the body switches to burning fat as its primary energy source. While fat provides long-lasting energy, it metabolizes much more slowly than carbohydrates. This switch leads to fatigue, reduced intensity, and mental fog—commonly known as "bonking"​.
To avoid hitting the wall, athletes must carefully manage their carbohydrate intake both before and during the race. Strategies like carbohydrate loading—increasing carb intake in the days leading up to the race—can help maximize glycogen stores. During the race, consuming sports drinks, gels, or energy bars can provide a steady supply of glucose to maintain energy levels and delay the onset of fatigue​.
In the next sections, we’ll delve deeper into strategies for maintaining energy throughout the race and avoiding glycogen depletion.

In endurance sports, race preparation is typically broken down into distinct phases, each with its own training focus and corresponding nutritional requirements. The base phase is the foundational period where athletes build aerobic capacity, endurance, and strength. This is also the time to address body composition goals, such as gaining muscle mass or reducing fat mass, to optimize performance.

During the base phase, athletes focus on developing fundamental endurance and overall fitness, often through low to moderate-intensity training sessions. Workouts during this phase include long-distance runs or cycles, strength training, and technical drills to improve form. The training volume is high, but intensity remains relatively low compared to later stages​.
Since training loads are high, the body’s energy needs increase, especially in terms of macronutrients. A balanced diet with appropriate levels of carbohydrates, proteins, and fats is essential during this period to support recovery, build muscle, and sustain energy levels. Athletes should aim for a diet where:

• Carbohydrates provide 45−60% of daily calories to fuel long training sessions and replenish glycogen stores.
• Protein intake should be around 1.2−1.7 grams per kilogram of body weight to support muscle recovery and repair.
• Fats should make up 20−30% of the diet, as they provide slow-burning energy and support overall cellular functions.

In the base phase, nutrition should be tailored to the specific training sessions and body composition goals:

1. Endurance Training: Focus on consuming more carbohydrates to sustain long training sessions. Including whole grains, starchy vegetables, and fruits ensures a steady release of energy.
2. Strength Training: Prioritize both carbohydrates and proteins for optimal muscle repair and growth. For example, consuming carbs and protein in a 3:1 ratio post-workout can enhance recovery.
3. Body Composition Goals: Athletes aiming to lose fat or gain muscle should adjust their diet accordingly. For fat loss, a slight caloric deficit while maintaining high protein intake can help retain muscle mass. Conversely, for muscle gain, a caloric surplus with higher protein intake will support muscle growth​.

Athletes should remember that during the base phase, the emphasis is on laying the foundation for future race-specific training. Therefore, it’s crucial to establish healthy and effective eating habits now, as they will play a key role in later phases when the intensity ramps up.

As endurance athletes transition from the base phase to the pre-competition phase, the focus shifts from building volume to refining race-specific intensity. During this period, training intensity increases while overall volume decreases. The goal is to sharpen lactate threshold, improve power, and maximize endurance without overloading the body. As the training changes, so should the nutrition strategy to meet these new demands.

During the pre-competition phase, athletes incorporate lactate threshold training and high-intensity interval training (HIIT) to increase their ability to sustain higher intensities and delay fatigue. Workouts simulate race conditions, which helps athletes build tolerance to the production of lactic acid and enhance their performance under stress​.
Nutritional strategies in this phase must support these specific goals. Carbohydrate intake is crucial to fuel the more intense workouts, and protein consumption aids in recovery and muscle repair. Nutrition plans should now emphasize carbohydrate loading and efficient glycogen replenishment​.

This phase is the ideal time to test nutrition strategies under race-like conditions. Athletes can practice consuming large volumes of carbohydrates during training to see how their bodies tolerate various sports gels, drinks, and foods. The goal is to ensure that gastrointestinal distress (such as diarrhea or nausea) is minimized during the race​.
For athletes, gut training involves gradually introducing larger amounts of carbohydrates during training sessions to improve the body’s ability to absorb and utilize glucose without causing digestive issues. This process is particularly crucial for endurance events, where the ability to consume fuel without discomfort directly impacts performance​.

Hydration is another key focus during the pre-competition phase. Athletes should use this time to experiment with electrolyte replenishment strategies, particularly when practicing in hot conditions. Some may even try dehydration training—controlled exposure to low hydration states to simulate race day conditions where water might not be as readily available. The goal is to protect against unexpected dehydration during a race, which can quickly impair performance and increase the risk of heat-related issues.
Overall, the pre-competition phase helps athletes prepare their bodies to handle the stress of high-intensity race conditions while testing nutrition and hydration strategies to ensure peak performance on race day.

The final two weeks before a key race are known as the taper period. During this phase, the focus is on reducing training volume while maintaining intensity. The goal is to allow the body to fully recover from the cumulative fatigue of the training cycle, ensuring you arrive at the starting line feeling fresh and energized.

As training volume decreases by about 40−60%, it’s crucial to maintain training intensity through shorter, high-quality sessions. This helps retain the neuromuscular and physiological adaptations gained during training without overloading the body. This gradual taper helps prevent detraining while promoting recovery.

During the taper, it’s important to adjust your caloric intake to match the reduced training load. Without these adjustments, the reduced calorie burn can lead to unwanted weight gain, as glycogen storage involves water retention, increasing body weight. This is especially critical since carrying excess weight on race day can negatively impact performance​.
To prevent this, athletes should focus on a balanced diet that emphasizes carbohydrates for glycogen storage without excess calorie intake. Carbohydrate intake should remain high (around 7−10 grams per kilogram of body weight) to ensure full glycogen stores, but total caloric intake should decrease to reflect reduced energy expenditure.

This is the ideal time to fine-tune race-day nutrition strategies, particularly carbohydrate intake and hydration. Practice race-day fuelling plans to ensure the body can tolerate large amounts of carbohydrates without gastrointestinal issues. Common practices include testing sports drinks, gels, and solid foods that will be used on race day​.

In endurance competitions, nutrition plays a pivotal role at every stage of the event. There are five key periods during race day that athletes must prepare for: Preparation, Pre-Start, During the Race, Immediate Post-Race, and Recovery. Each of these stages has unique nutritional needs designed to optimize performance, hydration, and recovery. Below is an in-depth look at how to manage nutrition during each stage.

In the days leading up to the race, the focus is on carbohydrate loading to maximize muscle glycogen stores. This practice, known as glycogen supercompensation, involves increasing carbohydrate intake to 8−12 grams per kilogram of body weight for 36−48 hours before the race​. Athletes should focus on consuming low-fiber, easily digestible carbs like white rice, potatoes, and pasta, while minimizing fat and fiber to reduce gastrointestinal distress​.

On the morning of the race, the primary goal is to replenish liver glycogen, which depletes overnight. A light, carbohydrate-rich breakfast (1−4 grams of carbs per kilogram of body weight) should be consumed 2−4 hours before the race. Good options include oats, bananas, or a smoothie. It’s also critical to focus on hydration by consuming water or an electrolyte solution to ensure proper fluid balance at the start line​.
Fifteen minutes before the start, consuming a small amount of fast-digesting carbohydrates (like an energy gel or sports drink) can "top off" glycogen stores and provide a final energy boost before the race begins​.

Once the race begins, the focus shifts to maintaining energy and hydration levels. For races lasting more than an hour, athletes should aim to consume 60−90 grams of carbohydrates per hour. This can be done through sports drinks, gels, and energy bars, preferably a mix of glucose and fructose to optimize absorption. Additionally, athletes should drink water and electrolyte solutions to maintain sodium balance and prevent dehydration.
For longer races, such as marathons or triathlons, caffeine may also be used to enhance mental focus and delay fatigue, though it’s important to test caffeine tolerance during training​.

After crossing the finish line, rapid glycogen replenishment becomes the priority. Within the first 30 minutes, athletes should consume a combination of carbohydrates (1−1.5 grams per kilogram of body weight) and protein (around 20−30 grams) to kickstart muscle repair and glycogen synthesis​.Drinking fluids with electrolytes will help rehydrate and restore sodium levels lost through sweat.

The recovery phase extends into the following day, where the focus is on replenishing muscle glycogen and fully rehydrating the body. Athletes should continue consuming high-carb meals, along with protein, to aid in muscle recovery. Electrolyte-rich drinks can further assist in restoring fluid balance​.

To ensure optimal performance on race day, it’s essential to follow a well-structured nutrition and hydration plan tailored to your body weight, the race duration, and the environmental conditions. Below is a suggested plan for a race without extreme conditions like excessive heat, cold, or high altitude.

Pre-Race Nutrition (1−4 Hours Before Start)

In the hours leading up to the race, the goal is to top off glycogen stores while ensuring proper hydration. Aim to consume 1−4 grams of carbohydrates per kilogram of body weight to provide a steady energy supply throughout the race.

• Example Meal: A bowl of oatmeal with dried fruits, a banana, or whole-grain toast with honey or jam.
• Hydration: 400−600 ml of water, a hypotonic solution, or an isotonic drink (5−7 ml per kg of body weight). This ensures hydration without overloading the stomach​.

1 Hour Before Start

As race time approaches, focus on small amounts of easily digestible carbohydrates:

• Carbohydrates: 25 grams of fast-digesting carbs, such as an energy gel, a small banana, or a piece of toast with jam .
• Hydration: 100−250 ml of water or an isotonic drink to ensure proper hydration without stomach discomfort .

During the Race

Carbohydrate intake during the race depends on the duration:

• For races lasting up to 2.5 hours: Target 30−60 grams of carbohydrates per hour. This can be achieved through energy gels, sports drinks, or bars.
• For races longer than 3 hours: Increase the intake to 90 grams per hour or more, using a combination of glucose and fructose to optimize absorption .

Hydration: Aim to consume 150−350 ml of water or isotonic drink every 15−20 minutes, adjusting based on sweat rates and race conditions. Testing different combinations of gels, bars, and drinks during training is essential to avoid gastrointestinal issues and ensure adequate hydration.

Post-Race Nutrition (Within 2−3 Hours After the Race)

Immediately after finishing the race, focus on replenishing glycogen stores and promoting muscle recovery:

• Carbohydrates: 0.8 grams per kg of body weight.
• Protein: 0.4 grams per kg of body weight. This ratio helps speed up recovery and repair muscle damage .

Example: A recovery shake containing both carbs and protein, or a meal such as rice with chicken or a high-protein smoothie.

Recovery (24 Hours Post-Race)

During the recovery period, focus on restoring full glycogen stores and fluid balance:

• Carbohydrate Intake: Aim for 8−10 grams per kg of body weight throughout the day to fully restore glycogen stores .
• Hydration: Drink 150% of fluid losses using drinks that contain 60 mmol/L of sodium. This helps retain fluids and rehydrate the body effectively.

This plan ensures athletes meet their carbohydrate and hydration needs during the critical phases of race preparation, execution, and recovery, maximizing performance while minimizing the risk of fatigue or gastrointestinal issues.

Proper nutrition is the foundation of endurance performance. From carbohydrate loading in the days leading up to the race to carefully timed carbohydrate and hydration strategies during the event, a well-planned nutrition strategy can make the difference between hitting your personal best or "hitting the wall." By fine-tuning your plan based on body weight, race duration, and personal tolerance, you can maximize glycogen stores, stay hydrated, and maintain energy levels throughout the race.
Don’t forget the importance of recovery after the event—glycogen replenishment, protein intake, and hydration are crucial to repairing muscles and restoring full energy levels for future training or races.
Ready to take control of your race day nutrition? NeverLow can help you create a personalized, race-specific nutrition plan to optimize your performance and recovery. Get started with NeverLow today and fuel your journey to success!