What to eat during endurance running? Your complete fueling guide

According to research published via the Gatorade Sports Science Institute, endurance athletes benefit from carbohydrate intakes ranging from 30 to 90 grams per hour for activities lasting over 60 minutes. Understanding what to eat during endurance running is crucial for maintaining energy, preventing fatigue, and sustaining your pace throughout long distances.

Quick Summary

An effective endurance running nutrition strategy centers on consistent carbohydrate intake, proper hydration with electrolytes, and training your gut to absorb fuel efficiently. Tailor your plan with different fuel types.

Key Points

• Carbohydrates are key: For runs over an hour, aim for 30-90 grams of carbohydrates per hour to replenish glycogen stores.

• Train your gut: Practice your fueling strategy during long training runs to ensure your digestive system can handle the fuel on race day.

• Hydrate consistently: Drink 4-8 ounces of fluid every 15-20 minutes, adjusting for temperature and sweat rate.

• Replenish electrolytes: During longer or hotter runs, add electrolytes like sodium to your hydration to prevent cramping and maintain fluid balance.

• Nothing new on race day: Stick to the products and routines you have perfected in training to avoid GI distress on race day.

Why fueling is critical for endurance running

During high-intensity or prolonged exercise like endurance running, your body's primary fuel source is carbohydrates, stored in your muscles and liver as glycogen. Your body has a limited capacity to store this glycogen. Once these stores are depleted—which typically occurs after 60 to 90 minutes of continuous running—performance suffers, a phenomenon commonly known as "hitting the wall." The only way to delay this is by consistently replenishing carbohydrates during your run through food and fluids.

Intake of carbs during a long run serves two main purposes: it provides a readily available energy source and spares your limited glycogen reserves. This allows you to maintain a higher intensity for a longer period. Moreover, proper fueling is key to avoiding gastrointestinal (GI) distress, a common complaint among long-distance runners.

The Golden Rules of Endurance Fueling

To build a robust fueling strategy, follow these key principles:

• Replenish carbs regularly: The longer and more intense your run, the more carbs you need. For runs over 60 minutes, start fueling early (around 30-45 minutes in) and aim for a consistent intake of 30-90 grams of carbs per hour. Don't wait until you feel hungry or low on energy; by then, it's often too late.
• Train your gut: Your stomach, like any other muscle, can be trained. Practice your race-day fueling strategy during long training runs to help your digestive system adapt to processing food while exercising. This is essential for preventing stomach issues.
• Use multiple carbohydrate sources: For higher carb intake (above 60g/hr), studies show that consuming a mix of carbohydrate types, such as glucose and fructose, can increase absorption rates and reduce the risk of GI distress. Look for sports nutrition products that contain a 2:1 glucose-to-fructose ratio.
• Nothing new on race day: Stick to the nutrition products and strategies you have successfully tested during your training. A new energy gel or sports drink on race day is a recipe for disaster.

Fueling options for endurance runners

The market offers a wide variety of fueling products, from engineered gels to natural foods. The best option for you depends on personal preference and gut tolerance. Testing is key.

Comparison of Common Fueling Options

Fuel Type	Pros	Cons	Best For
Energy Gels	Quick, concentrated carbs; easy to carry.	Can be messy; some find them difficult to stomach.	Fast energy boost during intense phases or late in a race.
Energy Chews/Blocks	Solid form, easy to portion; good taste variety.	Can be chewy and harder to eat while breathing heavily.	Steady, controlled carb intake throughout the run.
Sports Drinks	Replaces both carbs and electrolytes; aids hydration.	Can be bulky to carry; some contain too much sugar.	Consistent fuel/hydration, especially in hot weather.
Real Food	Natural ingredients; less chance of GI issues for some.	Less portable; potentially harder to digest during high intensity.	Slow-release energy; useful for long, steady efforts.
Dried Fruit (e.g., Raisins)	Portable, natural sugar source; electrolytes (potassium).	High fiber can cause stomach issues for some.	An easy-to-carry alternative to processed products.

The crucial role of hydration and electrolytes

Proper hydration is just as important as fueling. Dehydration can impair performance and increase the risk of heat-related illness.

• Fluid intake: Aim for 4-8 ounces of fluid every 15-20 minutes, especially in warmer conditions. Consider your individual sweat rate, which can be measured by weighing yourself before and after a run.
• Electrolyte replenishment: You lose essential electrolytes, primarily sodium, through sweat. Sodium is critical for maintaining fluid balance and muscle function. For runs over an hour, adding electrolytes via a sports drink or salt tablets is advisable. Recommendations for sodium intake vary but can be in the range of 300-900mg per hour, depending on your individual sweat rate and the climate.

Troubleshooting common nutrition issues

Even with a plan, issues can arise. Here are solutions for typical problems:

• GI Distress: Often caused by high-fiber, high-fat, or high-protein intake close to or during a run. Experiment with low-fiber foods and smaller, more frequent fuel portions during training. Multiple carbohydrate sources can also improve gut tolerance.
• "Hitting the Wall": This happens when glycogen stores are depleted. The solution is consistent fueling from the start. Start your carb intake 30-45 minutes into your run, and don't skip a fueling cycle.
• Cramping: Can be a sign of dehydration and electrolyte imbalance. Ensure you're hydrating adequately and consuming enough electrolytes, especially sodium, during your runs. Some runners also find a pre-race electrolyte supplement helpful.

Sample fueling strategies for different distances

Here are some simple plans to get you started, assuming you have practiced these methods in training.

For a 90-minute run:

• Start: Ensure you have eaten a light, carb-rich meal 2-3 hours before. Drink 8-16 ounces of water.
• During: Take your first energy gel or a few chews at 45 minutes, followed by another at 75 minutes. Sip water consistently throughout.
• Post-run: Have a mix of carbs and protein within 30-60 minutes for recovery.

For a marathon (or longer):

• Start: Follow a carbohydrate-loading strategy in the 24-48 hours prior. Consume a light, carb-rich breakfast 2-3 hours before.
• During: Aim for 60-90g of carbs per hour, starting early. Use a combination of gels, chews, and sports drinks. For example, a gel every 40-50 minutes, with consistent sips of sports drink and water between. Incorporate electrolytes.
• Post-run: Prioritize carbs (1.0-1.2 g/kg) and protein within the first four hours for glycogen replenishment and muscle repair.

Conclusion: Practice makes perfect

Optimizing your nutrition during endurance running is a personalized process. The core principles—consistent carbohydrate intake, proactive hydration, and electrolyte balance—are universal, but how you implement them will depend on your body's unique needs and tolerances. The most important takeaway is to experiment with different fuels and timing strategies during your long training runs. This approach of "training your gut" is the only reliable way to discover what works for you, ensuring that on race day, your nutrition becomes a performance advantage, not a point of failure.

For more expert advice on sports nutrition, consider exploring the resources at the Gatorade Sports Science Institute.

Final thoughts on optimizing your endurance diet

Ultimately, a successful endurance fueling plan is built on a foundation of experimentation and consistency. By understanding the science, testing different products, and listening to your body, you can create a strategy that not only prevents performance drops but helps you push beyond your perceived limits.

Frequently Asked Questions

How many carbohydrates should I eat per hour during an endurance run?

For endurance exercise lasting over 60 minutes, the recommendation is typically between 30 and 90 grams of carbohydrates per hour. The optimal amount can vary based on the duration and intensity of your run, as well as your body's absorption capabilities.

When should I start fueling during a long run?

You should start fueling early, around 30 to 45 minutes into your run. Waiting until you feel low on energy or hungry is often too late, as your glycogen stores will already be significantly depleted.

Are energy gels better than real food for endurance running?

Neither is inherently 'better'; it depends on individual tolerance and preference. Gels offer quick, concentrated carbs, while real foods like bananas or pretzels provide more natural energy. Practice with both in training to see what works best for your stomach and energy needs.

How do I know if I'm consuming enough electrolytes?

If you are a heavy sweater or running in hot conditions, you likely need electrolyte supplementation. Signs of deficiency can include cramping and fatigue. Consider your sweat rate and add salt tablets or an electrolyte-rich sports drink for runs over 60 minutes.

What's the best way to avoid GI issues while running?

To prevent GI distress, train your gut by practicing your fueling strategy, avoid high-fiber, high-fat, and high-protein foods before and during your run, and use a variety of carbohydrate sources to enhance absorption.

Should I drink water or sports drinks during my run?

For runs under 60 minutes, water is generally sufficient. For longer runs, a sports drink can be beneficial as it provides both fluid and carbohydrates, as well as electrolytes lost through sweat. For long runs, combining both can be effective.

What is carbohydrate loading, and is it necessary for endurance runners?

Carbohydrate loading involves increasing carbohydrate intake in the 24-48 hours before an endurance event to maximize glycogen stores in the muscles. It can benefit runners tackling longer distances like marathons.