If you’re a runner, you’ve probably heard that running a marathon burns a lot of calories. But just how many calories does it burn?

If you’re short on time, here’s a quick answer to your question: A marathon can burn between 2,500 and 3,500 calories, depending on your weight and running pace.

In this article, we’ll explore the science behind calorie burning during a marathon, factors that affect calorie burn, and tips for fueling your body during the race.

The Science Behind Calorie Burning

Calories are units of energy that our body uses to fuel all its functions, including exercise. When we exercise, our body burns calories to provide energy for muscle contraction, breathing, and maintaining body temperature. The number of calories burned during exercise depends on various factors such as the intensity, duration, and type of exercise, as well as the individual’s body weight, age, and gender.

When we engage in physical activity, our muscles use a combination of carbohydrates and fat as fuel. The more intense the exercise, the more carbohydrates our body uses as a source of energy. In contrast, low-intensity exercise such as walking or jogging primarily uses fat as fuel.

Running a marathon is an intensive physical activity that requires a large amount of energy. A typical marathon is 26.2 miles long, and the average runner completes it in about 4.5 hours. During this time, the body burns an average of 2,600 to 3,500 calories, depending on the individual’s weight and running pace.

This high calorie burn during a marathon can be attributed to several factors. First, running a marathon requires a significant amount of muscle contraction, which expends a lot of energy. Second, the long duration of the race means that the body has to continuously supply energy to the muscles, leading to a sustained calorie burn. Third, the body uses a larger proportion of carbohydrates as fuel during a marathon, which leads to a higher calorie burn compared to low-intensity exercise.

Factors That Affect Calorie Burn

If you’re wondering how many calories a marathon burns, it’s important to understand that there are several factors that can affect the number. Here are the top five factors that play a role in calorie burn during a marathon:

  • Body weight: It’s simple: the heavier you are, the more calories you’ll burn. This is because it takes more energy to move a heavier object. According to Runners World, a 150-pound person can expect to burn around 2,600 calories during a marathon.
  • Running pace: The faster you run, the more calories you’ll burn. This is because you’re working harder and expending more energy. According to Verywell Fit, a 160-pound person running a marathon at a pace of 8 minutes per mile can expect to burn around 3,000 calories.
  • Gender: Men tend to burn more calories than women during exercise because they have more muscle mass. However, this difference is not significant enough to make a huge impact on calorie burn during a marathon.
  • Age: As we age, our metabolism slows down, which means we burn fewer calories at rest and during exercise. However, this effect is not significant enough to make a huge impact on calorie burn during a marathon.
  • Fitness level: If you’re in better shape, you’ll burn fewer calories during a marathon because your body is more efficient at using energy. However, this doesn’t mean you won’t burn a significant number of calories. Even elite athletes can burn upwards of 2,000-3,000 calories during a marathon.

Ultimately, the number of calories you burn during a marathon will depend on your unique circumstances. However, by taking these factors into account, you can get a rough estimate of how many calories you’ll burn and adjust your nutrition plan accordingly.

Tips for Fueling Your Body During a Marathon

Marathon running is an intense physical activity that requires a lot of energy. To successfully complete a marathon, you need to fuel your body with the right nutrients. Here are some tips for fueling your body during a marathon:


Carbohydrates are the primary source of energy for your body during a marathon. It is recommended that you consume 30-60 grams of carbohydrates per hour of running. This can come from sources such as sports drinks, gels or bars. You should experiment with different types of carbohydrates during training to see what works best for you.


Protein is also important during a marathon as it helps repair and rebuild muscle tissue. However, it is important to note that your body cannot effectively digest protein during exercise. It is recommended that you consume protein after your run. This can come from sources such as lean meats, eggs or protein shakes.


Staying hydrated during a marathon is crucial. Dehydration can cause fatigue, cramps, and even heatstroke. It is recommended that you drink 17-20 ounces of water or sports drink every hour of running. You should also drink enough fluid to replace the sweat you lose during the run.


Electrolytes are minerals such as sodium, potassium, and magnesium that help regulate fluid balance in the body. During a marathon, your body loses electrolytes through sweat. It is important to replace these electrolytes to avoid cramping and maintain proper muscle function. You can consume electrolytes through sports drinks or electrolyte tablets.


Caffeine is a stimulant that can help improve endurance and reduce fatigue. It is recommended that you consume caffeine in moderation, as too much can cause dehydration and stomach upset. You can consume caffeine through coffee, tea, or energy gels that contain caffeine.

Remember, every runner is different, and the key to fueling your body during a marathon is to experiment with different types of fuel during training to see what works best for you. Also, consult with a sports nutritionist or doctor if you have any specific dietary needs or concerns.

How to Calculate Your Calorie Burn

If you’re training for a marathon, you may be wondering how many calories you can expect to burn during the race. While the exact number of calories burned will depend on various factors such as your weight, fitness level, and pace, there are several ways to estimate your calorie burn:

  • Using a fitness tracker: Many fitness trackers, such as Fitbit, Garmin, and Apple Watch, have built-in sensors that measure your heart rate and activity level to estimate your calorie burn. Make sure to input your weight and other personal information for more accurate results.
  • Online calculators: There are many online calculators that can estimate your calorie burn based on your weight, activity level, and duration of exercise. Some popular options include MyFitnessPal, HealthStatus, and CalorieKing.
  • The MET method: METs, or metabolic equivalents, are a measure of how much energy your body uses during physical activity. You can use the MET method to estimate your calorie burn by multiplying your weight in kilograms by the MET value for your activity. For example, running a marathon has a MET value of 13.3, so a 150-pound person would burn approximately 2,600 calories during the race.

Remember that calorie burn is just one aspect of marathon training and should not be the sole focus of your efforts. Proper nutrition, hydration, and rest are also crucial for a successful race. Consult with a healthcare professional before starting any new exercise program.


Running a marathon is a major accomplishment, and it can also be a great way to burn calories. By understanding how your body burns calories during exercise and fueling your body properly, you can optimize your performance and achieve your goals.

Remember, the number of calories you burn during a marathon will vary based on several factors, so it’s important to calculate your own calorie burn based on your body weight and running pace.

With these tips and tools, you can make the most of your marathon experience and enjoy the many benefits of this challenging and rewarding sport.

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