Nutrition Diet: What to eat before a long run?

October 23, 2025 •

4 min read

According to sports dietitians, consuming carbohydrates before and during runs over 60-75 minutes is crucial to maintain energy stores and prevent the dreaded 'bonk'. Mastering what to eat before a long run is, therefore, a foundational skill for any distance runner aiming to perform their best.

Quick Summary

Fueling for endurance running requires a strategic approach to timing and food choices. Prioritizing easy-to-digest carbohydrates while limiting high-fat and high-fiber foods can optimize muscle glycogen stores, sustain energy levels, and reduce digestive issues during training.

Key Points

Prioritize Carbohydrates: Focus on carbohydrate-rich meals and snacks, as these are the body's primary fuel source for endurance running.
Strategize Timing: Tailor your pre-run meal to the amount of time you have, opting for larger, balanced meals several hours out and smaller, simpler snacks closer to the run.
Limit High-Fiber and High-Fat Foods: Avoid foods high in fat and fiber right before a run to prevent stomach upset and slow digestion.
Stay Hydrated: Drink water and/or electrolyte-rich fluids in the hours leading up to and during your long run to maintain hydration and performance.
Practice During Training: Never test new foods or fueling strategies on race day. Experiment with options during your training runs to find what works best for your body.
Consider Caffeine Carefully: A small dose of caffeine may boost performance, but its effects are highly individual and should be trialed during training.
Listen to Your Body: Pay close attention to how different foods affect your energy levels and digestion, and adjust your plan accordingly.

The Science of Pre-Run Fueling

For endurance athletes, carbohydrates are the body's most efficient and readily available source of energy. During a long run, your body relies on glycogen—the stored form of carbohydrates in your muscles and liver—to power your efforts. While your body also uses fat for energy, especially during lower-intensity exercise, carbohydrates are essential for moderate to high-intensity running. Starting a long run with depleted glycogen stores will inevitably lead to fatigue, decreased performance, and a difficult training session. Therefore, strategically timing your meals and snacks is key to ensuring your energy reserves are topped off and ready to go.

Timing is Everything: Your Pre-Run Nutrition Schedule

Your eating plan for a long run is not a one-size-fits-all approach and depends heavily on how much time you have before you start running. The closer you get to your run, the simpler and more easily digestible your fuel source should be.

3 to 4 Hours Before: The Pre-Run Meal

This is the time for a substantial, balanced meal to top off your glycogen stores. This meal should be high in carbohydrates, moderate in protein, and low in both fat and fiber, which slow digestion and can cause gastrointestinal (GI) issues.

Complex Carbohydrates: Whole grains like oatmeal, rice, or pasta provide a steady release of energy.
Lean Protein: A moderate amount of protein aids in muscle repair and can help you feel satiated, but avoid overdoing it. Examples include eggs or lean chicken.
Examples: Oatmeal with a banana, a bagel with a thin layer of nut butter, or scrambled eggs with toast.

1 to 2 Hours Before: The Light Snack

If you have a shorter window, opt for a light, high-carb snack that is easy to digest. This helps to stabilize blood sugar without leaving you feeling heavy or bloated.

Good Options: A banana, a slice of toast with jam, or a small bowl of low-fiber cereal.
Why a banana? Bananas are packed with quick-digesting carbs and potassium, which can help prevent muscle cramps.

30-60 Minutes Before: The Quick Boost

For those who prefer to eat closer to their run, or need a final top-off, focus on simple sugars that provide a rapid energy spike. Liquid options are often tolerated best.

Best Choices: Energy gels, fruit chews, or a sports drink.
Note: If consuming an energy gel, pair it with water to aid absorption.

What to Prioritize in Your Pre-Run Meal

Carbohydrates: The cornerstone of your pre-run meal is carbs. Focus on easily digestible options, and consider increasing your carb intake in the 24-48 hours leading up to a race.
Hydration: Proper hydration begins well before your run. Drink 16-24 ounces of water or an electrolyte drink in the hours leading up to your run. Electrolytes like sodium are especially important for longer runs, as they help regulate fluid balance and muscle function.
Caffeine: For some runners, a moderate dose of caffeine 30-60 minutes before a run can decrease perceived exertion and increase alertness. However, this is highly individual and can cause GI distress in some. Experiment during training to see how your body reacts.

Foods to Avoid Before a Long Run

Equally important as what to eat is knowing what to avoid. Certain foods can cause GI distress, cramps, and discomfort during your run.

High-Fiber Foods: Whole grains, beans, and certain raw vegetables can be difficult to digest right before exercise.
High-Fat Foods: Fatty foods like fried items, creamy sauces, and excessive nuts or seeds slow digestion significantly.
Spicy Foods: Anything spicy can irritate the stomach and potentially lead to heartburn.
Large Amounts of Protein: While some protein is good, too much can sit heavily in your stomach.
Sugar Alcohols and Artificial Sweeteners: These can cause bloating and digestive upset.

Comparison of Pre-Run Fueling Timings


Time Before Run	Meal/Snack Type	Goal	Examples
3-4 Hours	Full, high-carb meal	Glycogen loading, sustained energy	Bagel with nut butter and banana; Oatmeal with berries
1-2 Hours	Light, carb-focused snack	Top-off glycogen, easy digestion	Banana; Toast with jam; Rice cakes
30-60 Minutes	Simple sugar boost	Quick energy, stabilize blood sugar	Energy gel or chews; Sports drink; Small handful of pretzels

The Importance of Experimentation

Fueling is a personal journey. What works perfectly for one runner can cause issues for another. The golden rule is to use your training runs to practice your nutrition strategy. This allows you to test different foods, timings, and quantities to discover what your body tolerates best. By the time race day arrives, your fueling plan should be a well-rehearsed, stress-free part of your routine.

Conclusion

A successful long run starts long before you lace up your shoes. By understanding the role of carbohydrates, respecting your body's digestion time, and avoiding potential triggers for GI distress, you can create an effective fueling strategy. The key lies in finding a balance between complex and simple carbohydrates, maintaining proper hydration, and—above all—experimenting during your training to build a plan that is uniquely yours. Proper nutrition is not just about finishing a long run; it's about finishing strong and feeling good while doing it.

This content is for informational purposes only and does not constitute medical advice. Consult with a healthcare provider or a registered dietitian for personalized nutrition guidance.

Frequently Asked Questions

For runs lasting more than 60-75 minutes, it is generally not recommended to run on an empty stomach. Your body needs carbohydrates to fuel prolonged, high-intensity exercise and prevent fatigue.

With only 30 minutes, opt for a small, simple carbohydrate source that is easy to digest. Good options include an energy gel, fruit chews, or a small banana.

While consistency can be helpful, the ideal pre-run meal depends on the specific run, your personal tolerance, and your overall diet. It's best to have a few go-to options that you've tested during training.

Yes, many runners consume coffee before a run, as caffeine can reduce perceived effort. However, it can also cause GI issues in some, so practice during training is essential to determine your tolerance and optimal dose.

The night before, focus on a high-carbohydrate dinner that is moderate in protein and low in fat and fiber to fully stock your glycogen stores without causing discomfort. Examples include pasta with a lean protein source or rice with chicken and vegetables.

Aim to drink 16-24 ounces of fluid, ideally containing electrolytes for longer efforts, in the few hours before your run. Continue sipping small amounts regularly up until you start.

Carb-loading involves increasing carbohydrate intake for 1-3 days before an endurance race longer than 90 minutes to maximize muscle glycogen stores. It is typically not necessary for regular long training runs.