How to properly fuel your body for running? A comprehensive nutrition guide

October 25, 2025 •

5 min read

According to research, up to 90% of long-distance runners experience some form of gastrointestinal distress during training or races. Mastering how to properly fuel your body for running is critical to prevent these issues, sustain energy, and optimize your overall performance. Proper nutrition is a strategic element of any training plan, whether for a 5k or a marathon.

Quick Summary

This guide provides a structured approach to running nutrition, detailing the best foods and hydration strategies for before, during, and after runs to enhance endurance and recovery.

Key Points

Timing is Everything: Strategically plan your carb and protein intake before, during, and after runs to maximize performance and recovery.
Carbs are Your Engine: Prioritize carbohydrates as your main energy source, using complex carbs for sustained energy and simple carbs for quick boosts.
Don't Forget Protein and Fats: Include moderate protein for muscle repair and healthy fats for sustained energy and nutrient absorption.
Hydrate Smartly: Drink water consistently throughout the day and use electrolyte-enhanced fluids for longer runs, especially in hot weather.
Practice Your Fueling Strategy: Test different foods, gels, and hydration plans during training to find what works best for your body and avoid race-day surprises.
Mind Your Gut: Avoid high-fiber and high-fat foods right before a run to prevent gastrointestinal distress.

The Core Principles of Runner's Nutrition

Proper running nutrition is built on three key macronutrients: carbohydrates, protein, and fats. Understanding the role of each is vital for creating an effective fueling strategy.

Carbohydrates: The primary and most efficient energy source for your body. They are stored as glycogen in your muscles and liver and are essential for fueling both high-intensity and long-duration efforts. Runners should consume both complex carbs (for slow-release energy) and simple carbs (for quick boosts) at appropriate times.
Protein: Crucial for muscle repair and recovery after runs. It helps rebuild the tiny muscle fiber tears that occur during exercise. Inadequate protein intake can increase injury risk.
Fats: Provide a slower, more sustained energy source, especially important for longer, lower-intensity runs. Healthy fats also aid in the absorption of fat-soluble vitamins (A, D, E, K), which are vital for overall health and immunity.

Pre-Run Fueling: The Foundation of Performance

What you eat before a run sets the stage for your performance. The timing and type of food depend on your run's duration and intensity.

For Long Runs (Over 90 minutes)

2-4 Hours Before: Consume a carbohydrate-focused meal with moderate protein and low fiber. This ensures your glycogen stores are topped off. Examples include oatmeal with a banana, a bagel with peanut butter, or pasta with a light sauce.
45-60 Minutes Before: A small, easily digestible snack with simple carbohydrates provides a quick energy boost. A banana, a handful of crackers, or a small sports drink work well.

For Short Runs (Under 60 minutes)

For shorter, easier runs, your existing energy stores are often sufficient. If you feel the need to eat, a small snack with simple carbs 30-60 minutes beforehand is enough. Some runners prefer running on an empty stomach for morning jogs.

Mid-Run Fueling: Sustaining Energy for Long Hauls

For runs lasting longer than 60-90 minutes, your body's stored glycogen begins to deplete, leading to fatigue (often called 'hitting the wall'). To prevent this, you need to refuel during the run.

Timing: Aim to consume 30-60 grams of carbohydrates per hour. This should be taken in small, frequent amounts (e.g., every 20-40 minutes) rather than all at once.
Sources: Sports drinks, energy gels, chews, or even easily digestible real foods like fruit snacks or dried fruit are excellent options. Experiment during training to find what your stomach tolerates best.

Post-Run Fueling: The Key to Swift Recovery

The period immediately following a run is a critical opportunity for recovery. Your muscles are most receptive to rebuilding their glycogen stores and repairing muscle tissue within 30 to 60 minutes after exercise.

Replenish Carbs: Consume a carbohydrate-rich snack to quickly replenish glycogen. A 3:1 or 4:1 carb-to-protein ratio is often recommended.
Repair with Protein: Include 20-25 grams of high-quality protein to kickstart muscle repair.
Excellent Recovery Options:
- Chocolate milk (naturally has a good carb-to-protein ratio)
- Yogurt with fruit and granola
- Smoothie with fruit, yogurt, and a scoop of protein powder
- Turkey sandwich on whole-grain bread

Staying Hydrated: Before, During, and After

Hydration is arguably as important as food. Dehydration can severely impact performance and cause muscle cramps and fatigue.

Before: Hydrate consistently throughout the day leading up to your run. Drink 16-20 ounces of water 2-3 hours before, and 6-8 ounces 15 minutes before starting.
During: For runs over 60 minutes, aim for 4-8 ounces of fluid every 15-20 minutes. For long runs or hot weather, sports drinks with electrolytes are better than plain water to replace lost minerals like sodium.
After: Drink 16-24 ounces of fluid for every pound of body weight lost during the run. Continue drinking consistently throughout the day.
The Role of Electrolytes: Especially important for heavy sweaters or long runs. Electrolytes like sodium, potassium, and magnesium help regulate fluid balance, muscle function, and nerve signals.

Comparison of Fueling Strategies for Different Run Distances


Aspect	Short Run (5k, <60 min)	Medium Run (10k-Half Marathon, 60-90+ min)	Long Run (Marathon+, 90+ min)
Pre-Run Meal	Optional light snack with simple carbs 30-60 min before.	Carb-focused meal with moderate protein 2-4 hours before.	Carb-focused meal with moderate protein 2-4 hours before; consider carb-loading 1-2 days prior.
In-Run Fuel	Not typically needed, existing stores sufficient.	Start consuming simple carbs (30-60g/hour) after the first hour.	Consume 30-60+g of carbs per hour from gels, drinks, chews, or food.
Hydration	Water to thirst, focus on pre-hydration.	Water every 15-20 minutes. Electrolytes on hotter days or if you sweat heavily.	Water and electrolytes consistently. Use sports drinks or tabs to supplement.
Post-Run Recovery	Small carb/protein snack (e.g., banana with nut butter).	Carb/protein-rich snack within 30-60 minutes.	Carb/protein-rich meal within 30-60 minutes, continue hydration.

Common Fueling Mistakes to Avoid

Trying New Foods on Race Day: Never experiment with new foods, gels, or drinks on race day. Your stomach may not react well, leading to GI issues.
Forgetting to Hydrate: Waiting until you feel thirsty often means you are already dehydrated. Hydrate consistently throughout the day and run.
Ignoring Fiber and Fat Timing: High-fiber and high-fat foods digest slowly and can cause stomach cramps during a run. Avoid these in the hours immediately preceding a workout.
Neglecting Gut Training: Just as you train your legs, you should train your gut. Practice your fueling and hydration strategies during long training runs to adapt your digestive system.
Focusing Only on Carbs: While carbohydrates are key, ignoring protein and healthy fats can hinder recovery and overall health.

Conclusion: Listen to Your Body and Plan Ahead

Mastering how to properly fuel your body for running is a journey of discovery and consistency. The perfect nutrition plan is highly individual and depends on factors like your body weight, training intensity, and environmental conditions. By understanding the roles of macronutrients, timing your meals correctly, and staying consistently hydrated, you can significantly enhance your running performance and recovery. Remember to use your long training runs as a chance to practice your race-day nutrition plan, ensuring no surprises come race day. For additional in-depth information, you can explore guides from expert sources like Sports Dietitians Australia.

Frequently Asked Questions

The best option is a carbohydrate-focused meal with low fiber, consumed 2-4 hours before your run. Examples include oatmeal with a banana or a bagel with a light spread. A small, simple carb snack like a banana can be had closer to the start.

For runs lasting less than 60-90 minutes, your body typically has enough stored energy (glycogen) and you do not need to consume extra food. A light snack beforehand is optional if you feel you need it.

For runs over 60 minutes, aim to drink 4-8 ounces of fluid every 15-20 minutes. On hot or humid days, or for long runs, use a sports drink with electrolytes to replace lost minerals.

Electrolytes are essential minerals like sodium, potassium, and magnesium that help regulate fluid balance, muscle contractions, and nerve signals. Runners lose these through sweat and need to replenish them, especially during long or intense sessions, to prevent cramping and fatigue.

Within 30-60 minutes after a run, consume a snack containing both carbohydrates and protein. This helps replenish glycogen stores and repair muscles. Chocolate milk, a turkey sandwich, or yogurt with fruit are great options.

Yes, some runners successfully use 'real food' like dried fruit or fruit snacks. However, this requires significant practice during training to ensure your stomach tolerates it well and avoids GI distress.

Carb loading is a strategy used before an endurance event (typically half-marathon or longer) to maximize your glycogen stores. It involves increasing your carbohydrate intake and reducing training volume in the 1-2 days prior to the race. It should be practiced during training first.