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How Many Calories Do You Burn in a Marathon?

Running a marathon is a dream goal that is realized by millions of people every year. It’s an excellent motivator to get fit, with the added benefit of soaking in the energy of other athletes out on the course and earning a race medal at the finish line. With more training and more miles comes more calories burned and weight loss, right? But, how many calories do you burn in a marathon?

Marathon training is hard on the body. Depending on the mileage base a runner starts with, a marathon training plan can last 12 to 20 weeks, and may or may not incorporate strength and running-specific cross training. That’s a long time to keep the motivation high enough to match the energy and miles needed to show up on race day as prepared as possible.

More mileage overall, especially the long runs, leave many athletes feeling depleted and hungry. Food is fuel, and it can be tricky to balance what your brain is telling you that you want or deserve to eat after a run against what the body actually needs. It’s easy to be under fueled, but it’s just as easy to overindulge.

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How Many Calories Do You Burn in a Marathon?

On average, runners will burn approximately 2,600 calories during a marathon. This is based on approximately 100 calories burned for each mile run. This is not a hard and fast rule so much as an estimate. Athletes running different paces, and body compositions, will burn calories at different rates during a marathon.

Research has shown that larger athletes, and those with more muscle, naturally burn more calories than people who are smaller and less muscular. Although, regardless of size, the harder the effort, the more energy expended, and the more calories burned. However, athletes that run faster spend less time on the course, so they may actually burn fewer calories than those runners in the back of the pack.

Smart watches, including sport and GPS watches, and apps like Map My Run do a sufficient job of estimating calories burned during a marathon. The technology leverages personal data input by the user about age, height, and weight and calculates that alongside MET data from sources like the Compendium and activity tracking details, such as distance and pace, to estimate caloric burn.

How Much Weight Do You Lose in a Marathon?

Basic weight-loss math outlines that to lose one pound per week, a person needs a 3,500-calorie offset. If the average marathoner burns 2,600 calories during a marathon, that’s nearly 75% of the caloric deficit needed to lose one pound. Including water weight, expect to lose 6-10lbs in a marathon.

If only the math were actually that simple. Marathoners consume calories during the race, because calories are fuel and fuel is needed for endurance and muscle function, so that offset isn’t necessarily being considered. Additionally, marathoners lose a lot of water weight through sweat. It’s important to remember that weight loss is a combination of fat, lean tissue, and water. So, while an athlete might find themselves lighter immediately after a race, the body will rehydrate and even out.

Many people actually gain weight while training for a marathon. The assumption is that the increased quantity and intensity or distance of the workouts offsets the food, but many people underestimate the number of calories that were burned during a workout, while also overindulging and eating more calories, assuming that the activity and food will cancel each other out. Although, some athletes that put an emphasis on strength training during marathon training might also see weight gain, but will lose inches in the process.

Afterburn Effect: How Long Do You Burn Calories After a Marathon?

During intense exercise, the body’s metabolic rate increases and stays elevated for a period of time after the workout ends. This period of time is known as the “afterburn effect.” The scientific name for this is excess post-exercise oxygen consumption, or EPOC. This lasts 24-48 hours post marathon.

Research has shown that the metabolism can remain elevated for several hours after a workout, with one study showing the potential for afterburn up to 38 hours post-workout. The calories burned during afterburn depends on a few things, including bodyweight, fitness level, muscle mass, and workout intensity and duration. Different workout types are more or less likely to result in a longer afterburn period.

It appears that high-intensity interval training (HIIT) and similar workouts with explosive periods of activity with rest periods result in a longer afterburn period than a marathon. This is because HIIT stimulates a higher EPOC due to consuming more oxygen during the workout, causing the afterburn period to be longer. HIIT fitness programs like Orange Theory operate on the concept of afterburn.


As for how many calories you burn in a marathon, this varies from person to person, with the average sitting around 2,600 calories. Marathoners might notice a drop in weight immediately after the race as the result of water-weight loss through sweat, but the scale will pick back up after rehydrating.

While the body is always burning calories, even at rest, afterburn is the sweet spot where the body is burning slightly more calories while resting, and marathoners can expect to benefit from some afterburn after the race. However, other activities, such as HIIT and sprints during marathon training, will result in a longer and stronger afterburn.

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About the author

Emily is an avid runner who has tackled distances from 5k to marathons. She volunteers at races whenever possible, and loves to encourage newbies to explore running.

Since 2018, she has maintained her RRCA Level I Certified Running Coach credential to be a more informed member of the running community when participating in conversations about training. In short, she really likes all things running.

Read more about Emily here.