Is it better to eat protein or carbs before a run?

December 22, 2025 •

5 min read

According to sports nutrition experts, carbohydrates are your body's primary and most efficient energy source for fueling a run, especially for moderate to high-intensity efforts. While protein plays a crucial role in muscle repair and growth, its contribution to immediate energy is minimal. The ideal choice depends on your run's intensity and duration, with most runners benefiting from prioritizing carbohydrates before exercise.

Quick Summary

Deciding between protein and carbs for a pre-run snack depends on timing, intensity, and duration. Carbohydrates are the main energy source, while protein aids recovery and muscle repair. A combination is often best, but the ratio shifts closer to race time. Timing is crucial for optimal digestion and sustained energy.

Key Points

Carbs are Primary Fuel: For most runs, especially high-intensity or long-duration ones, carbohydrates are your body's main energy source due to limited glycogen stores.
Protein Aids Recovery: Protein's primary role is muscle repair and synthesis after a run, not providing immediate energy during the activity.
Timing Matters: The closer you are to a run, the more you should prioritize easily digestible, simple carbohydrates and avoid large amounts of protein, fat, or fiber to prevent stomach issues.
Combine for Balance: For meals eaten 2-4 hours before a run, combining complex carbohydrates with a moderate amount of lean protein provides sustained energy and aids muscle preservation.
Match Fuel to Run: The duration and intensity of your run dictate your fueling strategy; short, easy runs may require less fuel than long, strenuous efforts.
Listen to Your Body: Individual tolerance varies greatly, so it is crucial to test different foods and timings during training to discover what works best for you.

Carbs vs. Protein: Understanding the Basics

When preparing for a run, the question of what to eat for fuel is paramount. The debate between carbohydrates and protein isn't about which is inherently 'better' for health, but rather which macronutrient serves as the most effective energy source for exercise. A 2020 review published in the Journal of the International Society of Sports Nutrition highlighted that glycogen, the stored form of carbohydrates, is the muscles' main energy source during moderate to high-intensity exercise. This means that for most running, carbs are the immediate go-to fuel, not protein. Meanwhile, protein's primary function is muscle repair and synthesis, crucial for post-run recovery, but not the primary driver of performance during the run itself.

The Importance of Carbohydrates for Runners

Carbohydrates are broken down into glucose, which is then either used for immediate energy or stored as glycogen in the liver and muscles. These glycogen stores are a limited fuel tank, and for runs lasting longer than 60 minutes, they can become depleted, leading to fatigue or 'hitting the wall'. This is why strategic carbohydrate intake is essential for endurance and high-intensity running.

Simple Carbohydrates: Digested quickly for a rapid energy boost, ideal for snacks within 60 minutes of a run. Examples include bananas, sports gels, and white toast with jam.
Complex Carbohydrates: Digested more slowly for a sustained release of energy, best for meals consumed 2-4 hours before exercise. Examples include oatmeal, whole-grain bread, and brown rice.

The Role of Protein Before a Run

While protein is not the primary fuel for running, a small amount can offer benefits, especially for longer runs. Protein can help slow the release of carbohydrates into the bloodstream, providing a more stable energy level and preventing crashes. However, too much protein before a run can lead to gastrointestinal distress because it takes longer to digest than carbohydrates. This is particularly true for high-fiber or high-fat protein sources. It is best to include a moderate amount of protein in a balanced meal eaten several hours before a run.

Timing is Everything: What to Eat When

The optimal pre-run meal or snack depends on the time you have for digestion and the duration of your run. It is important to experiment during training to find what works best for your body.

2-4 hours before: A balanced meal with a good proportion of complex carbohydrates, a moderate amount of lean protein, and limited fat and fiber is best. This allows for proper digestion and glycogen top-up without causing stomach upset.
45-60 minutes before: A smaller, easily digestible snack consisting primarily of simple carbohydrates is ideal. This provides a quick energy boost without a heavy feeling.
Less than 30 minutes before: Opt for easily digestible, liquid or gel-based simple carbohydrates if needed for a quick energy top-up.

Fasted Running: Is It a Good Idea?

For short, easy runs (under 60 minutes), some people prefer to run on an empty stomach, particularly in the morning. This can encourage the body to burn fat for fuel and may enhance fat-burning capabilities. However, fasted running carries risks, including decreased performance for high-intensity or long-duration efforts, potential muscle breakdown, and an increased risk of hypoglycemia. Beginners, those engaging in high-intensity training, or individuals with certain medical conditions should always eat beforehand.

Comparison Table: Pre-Run Carbs vs. Protein


Factor	Carbohydrates	Protein
Primary Function	Immediate energy, replenish glycogen stores	Muscle protection, repair, and synthesis
Energy Delivery	Fast-acting and most efficient fuel source for running	Slow to digest; not a primary energy source during exercise
Best For	Fueling endurance and high-intensity runs	Aiding long-term recovery and muscle health
Timing Pre-Run	Varies by carb type (fast vs. slow digestion)	Best consumed 2+ hours before exercise due to slow digestion
Ideal Snack Pairing	With a small amount of protein and fat (earlier)	As part of a balanced meal with carbohydrates
Considerations	Essential for runs over 60 minutes to prevent 'the wall'	Excessive amounts can cause GI discomfort while running

Example Pre-Run Snacks and Meals

Here is a list of effective pre-run options based on timing and duration:

Short, Easy Run (under 60 min, 30-60 min beforehand): A small banana, half a bagel with a thin layer of jam, or a handful of pretzels.
Morning Run (1-2 hours beforehand): A small bowl of oatmeal with berries, half a turkey sandwich on whole-wheat bread, or a fruit smoothie with a little protein powder.
Long or Intense Run (2-4 hours beforehand): A larger meal like pasta with a light tomato sauce and lean chicken, or rice with grilled tofu and a side of vegetables.

Conclusion: Finding the Right Balance for Your Run

In the debate of protein versus carbs before a run, carbohydrates emerge as the clear winner for immediate energy, particularly for longer or higher-intensity workouts. Protein serves a vital, but secondary, role in supporting muscle health and can be included in smaller, more moderate amounts in meals consumed several hours in advance. The best strategy is to balance both macronutrients in your overall diet, adjusting the ratio and timing based on your run's demands. Always test new fueling strategies during training to find what works for your body and helps you perform at your best. For specific nutritional needs and planning, consulting with a sports dietitian can provide personalized guidance and optimize your fueling strategy.

For more detailed, science-backed guidance on optimizing your fueling strategy, review the comprehensive guide on pre-workout nutrition from the Academy of Nutrition and Dietetics.

Summary of Pre-Run Nutrition

In essence, fueling a run is a strategic process tailored to the duration and intensity of your effort. For shorter, easy runs, a small, easily digestible carb snack or even a fasted state may be acceptable. However, longer or more intense sessions require a well-timed, carbohydrate-heavy meal to top off glycogen stores. Incorporating a small amount of protein can be beneficial, especially in meals eaten 2-4 hours before, to promote sustained energy and prevent muscle breakdown. The key is to listen to your body and find the right balance through trial and error during training. A registered dietitian can provide personalized guidance, but the general rule is clear: prioritize carbs for immediate energy, time your meals wisely, and use protein to support recovery rather than as primary fuel.

Frequently Asked Questions

For easy runs lasting less than 60 minutes, you can often run on an empty stomach. However, a small, easily digestible snack like a banana may still boost energy levels and prevent hunger.

Focus on simple, easily digestible carbohydrates such as a banana, applesauce, a handful of pretzels, or a slice of white toast with jam. These provide quick energy without causing stomach upset.

It is not ideal right before a run because protein takes longer to digest and can cause discomfort. A small amount of protein is fine if consumed in a balanced meal 2-4 hours prior, but closer to the run, prioritize carbs.

For longer runs, eat a full, carb-rich meal with a moderate amount of protein 2-4 hours beforehand. Examples include oatmeal with fruit and nuts, or a turkey sandwich on whole-grain bread.

Some experienced runners train in a fasted state to encourage the body to use stored fat for fuel. This is typically only done for low-intensity, shorter runs and carries risks of fatigue and muscle breakdown.

Yes, for meals eaten 2-4 hours before a run, a mix of carbs and a moderate amount of protein is recommended. For snacks closer to the run, prioritize carbohydrates.

Avoid foods high in fiber, fat, and excessive protein, as these are difficult to digest and can lead to gastrointestinal distress during your run. Examples include fried foods, heavy sauces, and legumes.

Extremely important. A pre-race meal rich in carbohydrates helps top off glycogen stores, ensuring you have the energy to maintain pace and avoid hitting 'the wall' during a long event.