How to fuel properly during a run?

November 14, 2025 •

5 min read

Proper fueling can improve running performance by up to 20% in long-distance events. Knowing how to fuel properly during a run is a critical skill for runners of all levels, moving beyond simple endurance to strategic energy management and injury prevention.

Quick Summary

This comprehensive guide explores the science of fueling for runners, detailing optimal timing for meals and snacks. It covers essential carbohydrate intake, hydration with electrolytes, and contrasts various mid-run fuel options. A post-run recovery plan and tips for training your gut are also included to enhance performance.

Key Points

Start Carbohydrate-Rich: Begin your runs with sufficient glycogen by eating a carb-focused meal or snack 30 minutes to 4 hours beforehand.
Refuel Mid-Run: For runs over 60 minutes, consume 30-60 grams of carbohydrates per hour from gels, chews, or real food to prevent energy crashes.
Prioritize Hydration and Electrolytes: Drink 5-10 fl. oz. of fluid every 15-20 minutes during your run, using an electrolyte-enhanced drink for longer or hotter efforts.
Train Your Gut: Practice your race-day fueling plan during training to condition your stomach and identify which fuels work best for you.
Optimize Recovery: Consume a 3:1 ratio of carbohydrates to protein within 30-60 minutes after your run to replenish glycogen stores and repair muscles.

The Science of Fuelling Your Run

To understand how to fuel properly during a run, you must first grasp the basics of energy usage. When you run, your body primarily uses stored carbohydrates, known as glycogen, as its main energy source. A typical runner has enough glycogen stored in their muscles and liver for about 60 to 90 minutes of continuous running. After this, your body begins to rely more on fat stores for energy, a less efficient process that leads to a significant drop in pace and a phenomenon known as 'hitting the wall.' Strategic fueling prevents this by topping up your glycogen stores before they are depleted.

Why Carbohydrates Are a Runner's Best Friend

Carbohydrates are the most efficiently metabolized energy source for high-intensity exercise. Without a steady supply, your body struggles to maintain pace and power. Simple, easy-to-digest carbohydrates are crucial both immediately before and during a long run. These provide a quick and accessible source of glucose to keep your blood sugar levels stable and your energy consistent.

Pre-Run Fueling: Laying the Foundation

What and when you eat before a run can dictate your performance. For runs under an hour, a small, easily digestible snack is often enough. However, longer efforts require more careful planning.

The 2-4 Hour Window

For longer runs (over 60-75 minutes) or intense workouts, eat a carbohydrate-rich, balanced meal 2 to 4 hours beforehand. This allows ample time for digestion and for your body to build up glycogen stores. Focus on complex carbohydrates combined with a little protein and fat to ensure sustained energy release.

Example meal ideas:

Oatmeal with bananas and a spoonful of nut butter.
A bagel with eggs or turkey and a slice of cheese.
Pasta with a light, non-creamy sauce and lean protein.

The 30-60 Minute Snack

If you're short on time or need a quick top-up, a small, carbohydrate-rich snack 30 to 60 minutes before your run is ideal. Opt for simple carbs that won't upset your stomach.

Quick snack ideas:

One large banana.
A handful of pretzels or crackers.
A few dates or raisins.
A sports drink or energy chews.

Fueling During the Run: Sustaining Your Effort

For runs exceeding 60 minutes, mid-run fueling is necessary. The goal is to consume 30-60 grams of carbohydrates per hour to maintain performance. For very long runs (over 2.5 hours), some elite athletes may increase this to 60-90 grams per hour by using a mix of glucose and fructose.

General guidelines:

Start fueling 30-45 minutes into your run to get ahead of glycogen depletion.
Take small, frequent amounts of fuel rather than large doses at once.
Experiment during training to find what works best for your stomach.

Choosing Your Mid-Run Fuel: Comparison

Selecting the right fuel depends on personal preference, gastric tolerance, and convenience. Here is a comparison of common options:


Feature	Energy Gels	Energy Chews	Real Food (e.g., Dates, Bananas)
Carb Delivery	Concentrated, fast-acting	Pre-portioned, moderately fast	Can be slower, depending on fiber content
Texture & Taste	Liquid/syrupy, comes in various flavors	Chewy, like candy; many flavors	Natural, may have a bulkier texture
Convenience	Easy to carry and consume on the move	Easy to carry, can be sticky to handle	Requires more storage, can be messy
Digestion	Can cause GI distress if taken without water	Less likely to cause issues than gels	Can be very easy to digest for many
Electrolytes	Many brands include sodium and other electrolytes	Often contain electrolytes	Must be supplemented separately or with salty food
Cost	Can be expensive	Moderate price point	Inexpensive, especially fruits

Hydration: More Than Just Water

Proper hydration is non-negotiable for runners. Your body loses fluid and electrolytes through sweat, and replacing them is critical for temperature regulation and preventing performance decline.

The Role of Electrolytes

Sweat contains essential electrolytes, primarily sodium, that help regulate nerve and muscle function. For longer or more intense runs, relying on water alone is not enough, especially for salty sweaters. Electrolyte replacement is vital to prevent issues like muscle cramping and hyponatremia.

Hydration Timing

Pre-run: Drink 17-20 fl. oz. of water about 2 hours before your run to start well-hydrated.
During run: Aim for 5-10 fl. oz. every 15-20 minutes. Consider an electrolyte drink for runs over an hour or in hot weather.
Post-run: Drink 16-24 fl. oz. for every pound of body weight lost to rehydrate fully.

The Critical Role of Post-Run Nutrition

Immediately after a run, your body is most receptive to refueling and repairing. The first 30-60 minutes post-run is a critical window to replenish glycogen and repair muscle tissue.

The 3:1 Ratio: Aim for a 3:1 ratio of carbohydrates to protein to maximize recovery. This combination helps restore depleted glycogen stores and kickstarts muscle repair.
Recovery Snack Examples: Chocolate milk, a fruit smoothie with protein powder, or yogurt with granola and berries.

Training Your Gut to Fuel

Just as you train your legs, you must also train your stomach. Gastrointestinal (GI) distress can be a significant barrier to effective fueling. Practicing your fueling strategy during training runs is essential to condition your stomach and avoid race-day surprises.

Start Small: Begin with small amounts of fuel and gradually increase as your stomach becomes accustomed to it.
Trial and Error: Experiment with different brands, flavors, and forms of fuel (gels, chews, real food) to see what your body tolerates best.
Consistency: Stick to a fueling routine to help your gut become efficient at processing food during exercise.

Conclusion: Perfecting Your Fueling Strategy

Learning how to fuel properly during a run is a process of trial, error, and consistency. The key is to see food as performance-enhancing fuel, not just sustenance. By developing a strategic plan for pre-run nutrition, consistent mid-run carbohydrate and electrolyte intake, and smart post-run recovery, you can unlock better performance, improve endurance, and enjoy your runs more. A well-fueled runner is a stronger, more resilient runner, ready to tackle any distance without hitting the wall.

Mayo Clinic Health System citation

Mayo Clinic Health System. "Fueling your run with good nutrition." https://www.mayoclinichealthsystem.org/hometown-health/speaking-of-health/fueling-your-run-with-good-nutrition.

REI Expert Advice citation

REI Expert Advice. "Running Nutrition: What to Eat." https://www.rei.com/learn/expert-advice/trail-running-nutrition-basics.html.

Frequently Asked Questions

For an early morning run, focus on simple, easily digestible carbohydrates like a banana, a small handful of pretzels, or a sports drink 30 to 60 minutes before you head out. This provides a quick energy boost without upsetting your stomach.

You should aim to consume 30-60 grams of carbohydrates per hour for runs over 60-75 minutes. This is best done by taking small amounts every 15-20 minutes, starting about 30 minutes into your run, to maintain steady energy levels.

For shorter, less intense runs, water is often sufficient. However, for runs over an hour or in hot, humid conditions, you lose essential electrolytes like sodium through sweat. Replenishing these with a sports drink or tablets prevents cramping and maintains proper bodily function.

Yes, many runners prefer real food options like dates, bananas, or energy bites. The key is to choose foods that are easy to digest, easy to carry, and that you have practiced with during your training runs to ensure they don't cause stomach upset.

Within 30-60 minutes of finishing, have a snack or drink with a 3:1 ratio of carbohydrates to protein. This helps replenish glycogen stores and start the muscle repair process. Examples include chocolate milk, a recovery smoothie, or yogurt with fruit and granola.

Hitting the wall is the point during a long run when your body has depleted its glycogen stores and must switch to burning fat for energy. This is a much slower process, causing a sudden and dramatic drop in energy. Proper mid-run fueling prevents this by continuously supplying carbohydrates to your system.

To prevent stomach issues, avoid high-fiber, high-fat, and spicy foods immediately before or during your run. Always test new fuels during training, not on race day, and take small, frequent sips of water with your fuel to aid digestion.