Fitness / Outdoor Running

Why You Might Gain Weight While Training for a Race

As a runner, you’re probably hungry all the time, but you still need to eat smart. Here’s how.

When you’re training for a big race, it’s easy to assume that you’re burning a ton of calories and that you “deserve” to eat whatever you want after each run.

However, it’s actually very common to gain weight while race training. On the flip side, your goal during race training isn’t weight loss, either, as that can lead to less energy, poorer recovery, and increased risk of injury.

If you need to prep for a big race, check out Aaptiv’s running workouts.

Our experts explain why you might gain weight while training for your next race, and how you can make small shifts to fuel properly and perform your best.

Not Eating Before or After a Training Run

Martise Moore, running coach and founder of GreenRunner, recommends eating something small before your training run. “I know it’s hard to make yourself eat before an early run, but do it anyway,” she says.

“It doesn’t need to be a full meal. It could be something light like a banana or peanut butter toast. If you don’t eat before your run, your body does not have enough fuel to perform well and you may feel like you’re starving after the run. That post-run hangry feeling can drive you to overeat and gain weight.”

It’s important to use the same approach after a run, too, even if you’re not that hungry. Eating a little snack within an hour of completing your workout can help keep your hunger in check so that you don’t overeat later on.

Certified Running Coach Mindy Solkin says that it’s very common for runners, especially those training for a half-marathon or marathon, to be more hungry and consequently eat more food—but you just need to make smart choices.

“Protein is a must after a run,” says Sophia Borghese, a nutrition and fitness consultant. “It helps your muscles recover and keeps you feeling full. Make sure to include this macronutrient in all pre- and post-run snacks. Good snack ideas are fruit and string cheese, chocolate milk, and protein shakes.”

Swapping Water for Sports Drinks

If you consistently feel hungry during race training, then take a look at your water intake. Dehydration might make you feel as though you’re starving when you’re really just thirsty.

Also, Moore warns against downing sports drinks after a run, due to excess calories and sugar found in most types. You can still enjoy sports drinks in moderation, such as during a run to help replace electrolytes and sugar, but try to focus on drinking water and eating hydrating fruits and vegetables, instead.

Overestimating How Many Calories You’re Burning

“Lots of runners overestimate the number of calories they’re burning while training,” notes Borghese. “As a result, they might give themselves permission to down a full six-pack of craft beer and eat five slices of pizza.

Unfortunately, active runners have caloric limits, too. These limits might be a little bit higher than they are for a sedentary person, but only 200 or 300 calories higher—so their diet shouldn’t be too much different than it is pre-race training.”

Personal Trainer Pam Sherman, who has been running for 40 years, experienced this firsthand as a runner. “It’s so common and easy to do, especially if you’re training for a longer distance event,” she says.

“The bottom line is energy balance. If we eat too much, we gain weight, plain and simple. Running long distances makes people hungry, and it’s easy to overeat because you’re starving after a run. I find people overestimate how much they burn versus how much they eat. Some use it as an excuse to overeat. I sure did and yup, gained weight!”

Both Sherman and Borghese use certain strategies during race training to keep weight gain at bay. First, Sherman says to journal your food every day, because it’ll help keep you on track. And according to Borghese, since it’s so easy to eat above your daily caloric expenditure, downloading a calorie track app on your phone is another way to stay within your limits while making sure that you’re fueling your body appropriately.

Too Many Post-Run “Treat Yo Self” Moments

We’ve all been there—you finish a challenging run, and immediately treat yourself to a delicious brunch, ice cream after dinner, a cocktail, and so on. However, those calories can add up extremely fast, and rewarding yourself with food during race training might lead to unnecessary weight gain.

Mentally, it’s tempting to think, “Oh, I’m running/working out so much, I can/should have this,” but one study indicated that people will eat more based on a workout if given the opportunity.

Sherman views this as one of the sneakiest ways that you can gain weight, even if you’re running all the time, and she advises foods high in fiber, protein, and fat to help you stay full longer, instead.

“Become the expert on your body,” she adds. “Know what food fuels you the best and keeps you the most full. This is a huge lesson and a really important one. Also, don’t become a carb-a-holic. Yes, we need carbs to fuel our runs, but we also need protein and good fats.

Make sure [that] all your meals have a combination of all. The old school big pasta dinner will just put you in a food coma—better to have some pasta, meat, and veggies for a balanced filling meal.”

Not Moving Much After Your Workout

Many runners eat more calories than they actually burn, says Borghese, which leads to weight gain. Additionally, after a long run, runners often spend the rest of the day sitting around, which further slows metabolism.

You can plan a perfect week of workouts, but if you only move your body during those specific time frames, you may still not be getting enough physical activity to counteract all the calories that you’re eating.

Running Slower Than You Think

Another element you may overestimate? How fast you’re running. Research shows that many people assume that they’re exercising much harder than they actually are, and it’s particularly true of beginner runners. If you’re new to running, then having a “just keeping running” or “just get to the finish line” mentality can be helpful for motivation, but it may also mean that your pace isn’t fast enough to burn as many calories as you think.

All Cardio With No Cross-training to Build Muscle

Of course, weight is just one piece of the puzzle when it comes to a successful run—your progress and performance also depends on body fat percentage or body composition and resting metabolic rate, says Solkin.

“There’s no secret that there is a symbiotic relationship between diet and exercise, but it’s important to know your personal numbers,” she says.

“Your Resting Metabolic Rate (RMR) shows the number of calories you burn at rest, and it will also show calories burned for activity and for exercise. Getting your body composition tested will show the difference between muscle and fat weight, which will help to know if you’re losing fat weight but keeping muscle weight. Therefore, the scale may show that you didn’t lose any weight, but you have replaced the fat with muscle, and gotten more toned.”

Runners should not only practice skills like sprint training but also add cardio cross-training to their weekly workout routine. Aaptiv has workout classes that can help you with that.

Borghese suggests staying active whether you’ve got running shoes on or not, and on rest days, fitting in at least 30 minutes of some other form of exercise, like yoga, strength training, or cycling.

“Strength training builds muscle and burns calories,” agrees Moore. “Whether you’re doing bodyweight exercises or lifting weights, you’ll promote lean muscle that continues to burn fat after you finish running. This will help you counteract those extra calories [that] you’re consuming during training.”

Fitness Outdoor Running


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