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The sneaky ways you can gain weight while training for a marathon

Training to run a half or full marathon requires a lot of dedication and many women are turning to this sport to help them lose weight. As the popularity of marathon running continues to soar in the United States, some women are startled to find that at the end of their big race, they’re heavier than when they began training.

Weight gain is very common in marathon training, especially in first-time distance runners,” says Carissa Bealert, a registered dietitian nutritionist, certified personal trainer and race announcer. She says, “First-time runners start [marathon training] as a ‘bucket list’ item with the notion that they’ll definitely lose weight due to all the extra activity and miles they’re running.”

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And she’s not talking about a few extra pounds due to muscle gain, but adding pounds of fat despite the grueling training regimen. “Training for and completing a marathon is no easy task,” suggests Bealert. She continues, “Training for a marathon and trying to lose weight is like trying to serve two different masters.”

Why do some women gain weight while training for a marathon?

“Most new runners, particularly those who are trying to lose weight, start out with relatively poor eating habits,” says Kim Watkins, running and functional fitness coach and CEO of inShape Fitness. She explains that despite the body’s need for more calories to keep up with the increase in exercise, many first-time marathon trainers reach for “reckless carbohydrate products,” which “curtails the body’s ability to utilize stored fat as its energy source.”

Watkins mentions that the “reckless carbohydrates” in a runner’s diet can be due to “poor replenishment choices,” including sugary sports drinks — a favorite beverage choice among marathon trainers. “Marathoners often consume sugary sports drinks and other food products that promote the idea of hydration, but add calories in the process,” she adds.

Bealert adds that weight gain may also just boil down to overestimating and overeating. “We runners, myself included, love to use a long run as an excuse to eat our favorite ‘not-so-healthy’ foods,” she says. Clarifying, she adds, “You may burn 1600 calories on a 16-mile run, but it’s not that cut and dry. Add in a 300-calorie breakfast, 200 calories of fuel during the run, 100 calories of sports drink and 200 calories of banana and protein post run. You’ve just consumed about half of your calorie burn, however when you sit down to your burger, fries and beers, you are overeating and extra calories equal weight gain.”

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How do you avoid gaining weight while training?

Since gaining weight is likely not the result you’re hoping for after months of hard work and training, you need to be aware of what you’re eating. “Make good food choices even though you are burning more calories,” advises Dr. Scott Weiss, a licensed physical therapist, board-certified athletic trainer, registered exercise physiologist and advanced personal trainer.

He points out, “Just because your hunger levels spike, and your calorie burn is high, it doesn’t mean it’s time to snack on ice cream and cake. Maintaining a sense of discipline with your food intake while training will prevent any unexpected weight gain from calories.”

Weiss also shared that during rigorous training, your body becomes better at storing carbohydrates for energy so making good food choices is important — even if you’re not actively running. “When you are plateauing in your training, or your training goes down, be very conscious of your food intake, and really only reach for what you need,” he adds.

What you eat isn’t the only thing you need to be aware of when you’re training for a marathon. Water and a healthy electrolyte balance are a part of the puzzle too. “Drink plenty of water,” advises Brandon Roberts, M.S., certified strength and conditioning specialist and exercise physiologist.

He continues, “Even up to a gallon [of water] a day is fine. Also, try to consume a 3:1 ratio of sodium to potassium — like Gatorade — before and after your runs,” which may help with any weight gain due to water retention.

What are you supposed to eat?

What you eat before and after your race is just as important as what you eat while you train. “The body needs fuel post-run with a balanced meal of protein, fat and carbohydrates within two hours,” recommends Emily Bailey, registered and licensed dietitian, board-certified specialist in sports dietetics and director of nutrition coaching at NutriFormance & Athletic Republic St. Louis.

She adds, “When someone is unable to eat after a run, later they become starving and when we are that hungry, the rational to make a healthy choice or portion is difficult and we overeat.” That means committing to making healthy food choices needs to be made a large part of training as well as how many miles your shoes take you.

If you’re struggling with meeting your nutritional and caloric demands while training for a marathon, seeking professional guidance is always a smart choice. “Meet with a registered sports dietitian to learn your individual fueling needs for training. Look for those who have the credentials R.D., L.D. and C.S.S.D. or a master’s degree in sports nutrition,” says Bailey.

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