Marathon Training for Weight Loss

Male runner stretching in shade.

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How far would you go to get the body you want? If the answer is 26.2 miles, then this article is for you. Many exercisers use marathon training for weight loss.

But running to lose weight doesn't always work. You have to know how to lose weight during training if you want to cross the finish line with a leaner, fitter body.

Weight Loss During Marathon Training

You might be surprised to know that many new marathoners don’t lose any weight during training. In fact, many people actually gain weight when they train for a marathon. Surprised? The situation is more common than you might expect.

Scan any running blog or online forum, and you'll find countless posts written by frustrated runners who (reasonably) expect to slim down as they slog through their weekly miles. But instead, race day arrives, and they are no leaner than the day they started training. So what's the problem?

Several issues come into play when you combine marathon training and weight loss. These issues may explain why you can't slim down when running.

Understanding these factors might also provide a sense of relief (don't're normal!) and lead you to a strategy for getting the results that you want.

Training May Increase Hunger

There is some scientific evidence showing that intense exercise and running, in particular, can lower hunger hormones and even lead to a decrease in food intake.

In one small 2016 study published in the journal Nutrients, researchers found that when 23 male long-distance runners completed a 20-kilometer run, their levels of the hunger hormone ghrelin decreased, subjective hunger was decreased.

The specific sample group consumed less food compared to the control group as a result. However, another hunger hormone, PYY, remained the same.

There were limitations to the study, such as the small sample size and the fact that meals consumed later that day and the day afterward were not recorded.

In another small study done in 2011, researchers evaluated the post-hunger levels of 10 males. They stated that "the effects of exercise on hunger sensations and food intake are fairly controversial and depend on the intensity and duration of exercise."

The bottom line is that exercise doesn't always have the same effect from person to person—it can make some people hungry and others less so. However, the overall exercise regimen has an appetite-reducing impact, as noted in the decreased ghrelin (hunger hormone) response.

Training May Decrease NEAT

Non-exercise activity thermogenesis (NEAT) is the name researchers use to define the energy (calories) expended from all of your daily movement that is not exercise. NEAT accounts for 60%–75% of the total calories you burn during the day. But there is wide variation in that number.

People who take the stairs, walk to the market, stand or walk around in the office, cycle to work or fidget more often burn more calories from NEAT. Those who have sedentary jobs, watch more television, and rest throughout the day burn fewer calories from NEAT.

Your marathon training can make you more tired than usual. As a result, you may be less active during your non-exercise hours. It's a condition that some call "sedentary athlete syndrome." In short, you might burn more calories from exercise but fewer calories from NEAT.

The loss in calories burned from NEAT might be substantial enough to impair weight loss or even cause weight gain.

Exaggerated Caloric Expenditure

It is easy to overestimate the number of calories that you burn during a workout. In fact, studies have shown that, as a general rule, we are not good at guessing the number of calories we burn during exercise.

A small study published in the Journal of Sports Medicine and Physical Fitness found that 16 normal-weight adults (8 men and 8 women) estimated their calories burned during exercise to be three to four times the actual number.

Further, when asked to precisely compensate for their exercise expenditure with food intake, the resulting energy intake was two to three times greater than the actual measured exercise expenditure.

Even if you wear a fitness monitor that tracks calories burned, the number can be inaccurate. Research consisting of 44 healthy adults has shown that while trackers are generally good at measuring heart rate, number of steps, distance, and sleep duration, they tend to be less accurate at determining calories burned during exercise.

How to Lose Weight While Marathon Training

Losing weight while training to run a marathon is possible. But it’s hard. In short, you've got two competing goals: one pushes you to eat more, and the other nudges you to eat less. If you take on both challenges at once, you'll need a solid strategy for success.

Use these tips to eat well, train smart, and perform at your best during training.


Working towards both your weight loss goal and the marathon goal simultaneously is possible, but you should prioritize one. Decide if it is most important to lose weight or most essential to complete your marathon.

Making the decision may depend on your current weight and state of health. For example, if you are overweight or obese, losing weight may help you run a marathon more comfortably and efficiently. Weight loss may also help to prevent injuries.

In this case, losing weight would be a wise priority. If training gets in the way of meeting weight loss goals, then postpone the marathon and reach a healthy weight first.

But if you are heavier than you'd like to be, yet not overweight, running may help you be more comfortable with your body. You might learn to love your body the way it is, based on what it can do rather than on what it looks like. This boost in confidence might help motivate you to reach your healthy weight loss goals.

In this case, marathon training would be a smart priority. If weight loss gets in the way of reaching your running goals, then postpone it. After the marathon, you may decide that you don't need to lose weight after all.

Meet Your Macros

Be sure to get balanced nutrition during training. Avoid diets that eliminate or severely restrict a food group, especially carbohydrates. Your best nutritional plan during training and performance will vary with intensity.

Someone exercising 2–3 hours per day at an intense level 5 to 6 times per week will need 5 to 8 grams of carbohydrates per kilogram of body weight per day or 250–1200 grams per day to maintain liver and muscle glycogen stores.

An athlete exercising 3 to 6 hours per day at an intense level in 1 to 2 daily workouts for 5 to 6 days per week would need to consume 8 to 10 grams of carbohydrates per kilogram of weight per day. This is about 400 to 1,500 grams of carbohydrates per day.

For protein, consuming 1.4 to 1.8 grams of protein per kilogram of weight is recommended. Finally, fat should make up the rest of the calories.

Choose Quality Carbs

Choosing high-quality carbohydrates will not only help you to fuel your runs more effectively, but it can also aid in weight loss.

Try to avoid refined grains and processed foods. Foods that contain added sugars, excess sodium, and saturated fat (usually called empty calorie foods) may disrupt your training and performance goals.

Instead, spend most of your carbohydrate allowance on filling and nutritious whole grains, fruits, and vegetables. These foods provide energy as well as essential vitamins and minerals.

However, keep in mind that immediately before and during your long runs, you need quick energy. On these occasions, lower fiber foods are generally recommended to avoid stomach upset.

Time Your Food Intake

If you're an evening runner and you've fallen victim to the late-night-eating habit, consider moving your biggest meal to the middle of the day. By eating most of your calories in the afternoon, you fill up on healthy foods and give your body the energy it needs in time for your workout.

You can also use meal prep strategies to improve your food timing. Prep healthy pre-and post-run snacks once each week and have them ready to go when you need them. Plan meals in advance and pre-cook as much as possible, so you aren't tempted to grab fast food when you're hungry.

Incorporate Strength Training

Running every day will wear your body (and your brain) down quickly. Take a few days each week to focus on strength training.

Doing bodyweight exercises or training with weights can help reduce the risk of running injuries. Also, it is not likely to make you as hungry as running. And most importantly, strength training builds muscle, and muscle helps you burn more calories at rest.

Choose Healthy Rewards

Choose non-food treats to reward your efforts. For example, after a long run, you might get a massage. After a challenging hill workout, get a pedicure or see a movie with a friend.

You honor the running achievement without derailing the weight loss attempt by finding healthy ways to celebrate your efforts.

Get Expert Help

Some runners can schedule their runs to train for a marathon. Some people who are trying to lose weight can plan nutritious meals. But juggling both at the same time is tricky. So why not ask for help?

Seek the guidance of a registered dietitian with knowledge and expertise in sports training or running. They can provide you with a meal plan, recipes, and tips to make your nutritional program easier to follow.

Your nutrition professional may also be able to help you sort through your goals. If marathon training and weight loss start to take over your life, it may be time to revisit your priorities and see which choice is more likely to promote better health and wellness.

A Word From Verywell

Training for a marathon is an exceptional accomplishment. Completing each day’s mileage despite typical daily distractions takes mental endurance, self-discipline, and focus.

Losing weight requires an identical effort. If you choose to take on both challenges simultaneously, you’ve got to double your investment to see results. But the payoff is extraordinary. Use these tips during your marathon training for weight loss and a strong performance on race day. 

6 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Vatansever-Ozen S, Tiryaki-Sonmez G, Bugdayci G, Ozen G. The effects of exercise on food intake and hunger: relationship with acylated ghrelin and leptin. J Sports Sci Med. 2011;10(2):283-291.

  3. Júdice PB, Silva AM, Magalhães JP, Matias CN, Sardinha LB. Sedentary behaviour and adiposity in elite athletesJ Sports Sci. 2014;32(19):1760-1767. doi:10.1080/02640414.2014.926382

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Additional Reading

By Malia Frey, M.A., ACE-CHC, CPT
 Malia Frey is a weight loss expert, certified health coach, weight management specialist, personal trainer​, and fitness nutrition specialist.