What to eat as an endurance athlete?

January 5, 2026 •

5 min read

Studies show that proper nutritional strategies can improve endurance performance by up to 3%. Mastering what to eat as an endurance athlete is therefore critical for sustaining energy, preventing fatigue, and optimizing your body's ability to perform under pressure and recover effectively.

Quick Summary

Effective nutrition for endurance sports requires strategic fueling before, during, and after exercise. The body relies on balanced intake of carbohydrates, protein, and healthy fats, with specific timing to maximize glycogen stores and support recovery.

Key Points

Carbohydrate-Centric Diet: Endurance athletes should build their diets around a high proportion of quality carbohydrates to fuel their long, intense efforts, aiming for 45-65% of daily calories.
Timing is Everything: Strategically time your nutrient intake by consuming carb-rich meals 2-3 hours before exercise, fast-acting carbs during long sessions, and a carb-protein mix within an hour post-workout.
Practice Gut Training: Practice your race-day fueling plan during training to condition your digestive system and prevent gastrointestinal distress during competition.
Prioritize Hydration: Maintain proper hydration throughout the day, and replace electrolytes, particularly sodium, during prolonged or hot events using sports drinks or tablets.
High-Carb is Optimal for Intensity: Unlike the ketogenic diet, a high-carbohydrate approach is superior for fueling the high-intensity bursts and overall aerobic efficiency required in most endurance races.
Don't Forget Micronutrients: Pay attention to vital micronutrients like iron, Vitamin D, and B vitamins, as deficiencies can negatively impact performance and recovery.

The Foundation: Macronutrient Balance

For an endurance athlete, the daily diet is the bedrock of success. While specific needs vary based on training intensity and body composition, a balanced intake of the three major macronutrients—carbohydrates, protein, and fat—is essential.

Carbohydrates: Your Primary Fuel

Carbohydrates are the most important energy source for high-intensity, prolonged exercise, stored as glycogen in your muscles and liver. Depleting these stores is what causes fatigue and the infamous 'bonk'.

Complex carbohydrates: Include foods like whole grains, oats, brown rice, and starchy vegetables (sweet potatoes, potatoes) to provide a slow and sustained release of energy throughout the day.
Simple carbohydrates: Use faster-digesting carbs like fruits, sports gels, or chews for quick energy during intense or long efforts. TrainingPeaks suggests aiming for 45-65% of your daily calories from carbohydrates.

Protein: For Repair and Recovery

Protein is critical for repairing muscle tissue damaged during intense training and for supporting overall immune function.

Lean protein sources include chicken breast, turkey, fish, eggs, and dairy products. Plant-based options like tofu, lentils, and beans are also great.
Endurance athletes may require slightly higher protein intake than sedentary individuals, with recommendations ranging from 1.4 to 1.6 grams per kg of body weight for elite athletes.

Healthy Fats: Long-Burning Energy

Healthy fats provide a concentrated and long-term energy source, particularly useful for lower-intensity, longer-duration activities where fat oxidation is higher.

Incorporate sources like avocados, nuts, seeds, and olive oil into your diet for sustained energy and other health benefits.

The Art of Nutrient Timing

When you eat is just as important as what you eat. Proper nutrient timing maximizes your body's ability to use fuel efficiently and recover effectively.

Pre-Exercise Fueling

Eating a carb-rich meal 2-3 hours before a long workout or race tops off your glycogen stores. The meal should be low in fiber and fat to prevent stomach issues.

2-3 hours prior: Oatmeal with banana and honey, or a bagel with peanut butter.
30-60 minutes prior (optional): A small, easily digestible carbohydrate snack like a banana or energy gel, especially if it's been a few hours since your last meal.

Fueling During an Event

For exercise lasting longer than 60-90 minutes, it's vital to take on additional carbohydrates to prevent glycogen depletion. Aim for 30-60 grams of carbs per hour, using a combination of fast-acting sources.

Best sources: Energy gels, chews, or electrolyte drinks containing a mix of glucose and fructose for optimal absorption.
Sustained intake: For efforts over four hours, consider adding a small amount of protein (up to 5g/hr) to help with muscle function and satiety.

Post-Exercise Recovery

The window immediately after exercise is prime for glycogen replenishment and muscle repair. Aim to consume a mix of carbohydrates and protein within 30-60 minutes post-workout.

Recommended ratio: A 3:1 carb-to-protein ratio is often suggested.
Recovery foods: Chocolate milk, a smoothie with fruit and protein powder, or a meal with lean protein and carbs (e.g., grilled chicken with sweet potato).

Hydration and Electrolytes

Adequate hydration is non-negotiable for endurance athletes. Dehydration can significantly impair performance and increase the risk of heat-related illness.

Drink fluids consistently throughout the day, not just during exercise.
For efforts lasting over an hour or in hot conditions, replace electrolytes (especially sodium) lost through sweat by using sports drinks or electrolyte tablets.

The Power of Practice: Gut Training and Carb Loading

Gut Training

Just as you train your muscles, you can train your gut to handle the stress of race-day fueling. This involves practicing your fueling strategy during long training sessions to avoid gastrointestinal issues during competition.

Gradually increase the amount of carbohydrates you consume during training sessions.
Practice with the exact products (gels, chews) and hydration you plan to use on race day.
Sports Dietitians Australia offers excellent guidance on fueling for endurance events.

Carb Loading

For events lasting longer than 90 minutes, carb loading can help maximize muscle glycogen stores. The modern approach involves increasing carbohydrate intake for 1-3 days before the event while tapering your training volume.

Aim for 10-12 grams of carbs per kg of body weight per day.
Choose low-fiber carbs like white rice, pasta, and potatoes to reduce the risk of GI distress.

High-Carb vs. Low-Carb (Keto) Diets: A Comparison for Endurance


Feature	High-Carb Diet	Low-Carb High-Fat (Keto) Diet
Primary Fuel	Carbohydrates (glucose/glycogen)	Fats (fatty acids and ketones)
Energy Efficiency	High; carbohydrates require less oxygen for energy production.	Lower; fat requires more oxygen per unit of energy produced.
Anaerobic Capacity	Excellent; carbohydrates fuel high-intensity efforts, like sprinting up a hill.	Limited; very little fuel for anaerobic efforts.
Sustained Performance	Excellent for long duration, but requires consistent fueling during exercise to avoid bonking.	Good for steady-state, low-intensity exercise, potentially lasting longer without frequent fueling.
Key Performance Insight	Better for races involving bursts of speed and sustained high intensity, which is common in many endurance sports.	Most research indicates it impairs peak performance in elite athletes, especially for high-intensity efforts.

Vitamins and Minerals for Endurance Athletes

While whole foods should be your primary source, some micronutrients are particularly important for endurance athletes, and deficiencies can impact performance.

Iron: Essential for oxygen transport in the blood. Female athletes and those on plant-based diets are at higher risk of deficiency.
Vitamin D and Calcium: Crucial for bone health, especially important for high-impact activities like running.
B Vitamins: Key players in energy metabolism, converting food into usable energy.

Conclusion: Fueling for Success

Understanding what to eat as an endurance athlete is a cornerstone of training and race-day performance. It requires a thoughtful and strategic approach, focusing on a balance of macronutrients, precise timing, and adequate hydration. Prioritizing whole foods while strategically incorporating sports nutrition products and addressing potential vitamin deficiencies will provide your body with the fuel it needs to perform at its best. By practicing your fueling strategy during training, you can ensure your gut is prepared, and your body is ready to go the distance on race day, avoiding the dreaded energy crash and maximizing your potential. The difference between a good race and a great one often comes down to the fuel in your tank.

Frequently Asked Questions

A good pre-race meal, consumed 2-3 hours before the event, should be high in easily digestible carbohydrates and low in fiber and fat to prevent GI issues. Examples include oatmeal with a banana, a bagel with a thin spread of peanut butter, or rice with some lean protein.

For races longer than 60-90 minutes, consume 30-60 grams of carbohydrates per hour. This can be achieved through sports gels, chews, or an electrolyte sports drink. For events over four hours, consider a small amount of protein as well.

Proper hydration is crucial because dehydration impairs performance, reduces power output, and can lead to muscle cramps and fatigue. Replacing both fluid and electrolytes lost through sweat is key, especially during hot conditions or long events.

Within 30-60 minutes after a workout, consume a snack or meal containing both carbohydrates and protein. A 3:1 carb-to-protein ratio is recommended to replenish glycogen stores and repair damaged muscle tissue.

No, for most endurance athletes, a high-carbohydrate diet is better for peak performance. While keto increases fat oxidation, it limits the body's ability to fuel high-intensity bursts and can reduce overall movement economy. High-carb diets are proven to fuel harder, faster efforts.

Gut training involves gradually increasing your carbohydrate intake during training sessions to condition your stomach to handle race-day fueling. This helps prevent nausea, bloating, and other GI distress that can sabotage a race.

Key micronutrients include B vitamins for energy metabolism, iron for oxygen transport, and vitamin D and calcium for bone health. Endurance athletes, especially women and plant-based athletes, may need to pay special attention to iron levels.