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Does Cardio Make You Gain Weight? Here's What The Experts Say

Sarah Kostyukovsky, PT, DPT, OCS
Medical review by
Sarah Kostyukovsky, PT, DPT, OCS
Sarah Kostyukovsky, PT, DPT, OCS, is an orthopedic physical therapist who specializes in treating pelvic floor dysfunction and the perinatal population. She earned her B.S. from the University of Virginia and her Doctorate of Physical Therapy from Columbia University College of Physicians and Surgeons. She is co-founder of Flow Physiotherapy and the owner of Mom in Balance New York, which offers pregnancy and postpartum outdoor fitness classes in Manhattan and Brooklyn.
Last updated on March 28, 2020

For decades, doctors have been ensuring patients struggling with their weight that the formula for losing pounds is simple: Just burn more calories than you take in. Unfortunately, when many people set out to achieve a calorie deficit, by running or spending time on the elliptical, they're met with less-than-stellar results. For some people, after a month of daily cardio, the scale doesn't always budge and some might actually gain weight.

What gives? The truth is, there isn't one tried-and-true method for weight loss, and for some people, cardio just isn't an effective way to lose weight—but there's more to it than meets the eye. Let's take a closer look.

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What the research says.

As the theory goes, one of the main reasons people either don't lose weight when they engage in regular cardiovascular activity is because all that movement makes them hungrier. While this concept has been studied for years, the latest research out of Loughborough University in Britain1 saw some interesting results.

The small study closely followed 16 healthy young men to see which types of exercise led to increased levels of acylated ghrelin, or the hormone that increases appetite. Interestingly, they found that when these men ran for 90 minutes or longer, their appetites were actually less voracious than the appetites of those who engaged in shorter, more intense bursts of exercise.

Of course, this is a small study, but the bottom line is that we're all different—and for some people, eating an enormous meal after exercise might have less to do with actual appetite and more to do with other factors.

Why exercise backfires.

Let's take a closer look at those other factors. Albert Matheny, M.S., R.D., CSCS, and co-founder of SoHo Strength Lab, says that for many of his clients who struggle with their weight, they mistake dehydration for hunger. "While cardio can make people hungrier, I often believe it's in their heads," he explains. "First, make sure you are hydrated. Second, make sure you are giving your body the nutrition it needs."

He adds that exercise is actually a great way to understand what your body needs, as we need to eat after exercise in order to repair the muscles. But he points out that a lot of people are addicted to carbohydrates, which messes with hunger cues. "Breaking the addiction most people have to carbohydrates is key," he says.

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Exercise as a weight-loss tool.

While exercise has a number of benefits that have absolutely nothing to do with weight loss—from happiness and decreased stress to reduced risk of heart disease—it can be an effective way to lose weight if you do it right.

"Cardiovascular fitness, strength training, and mobility should both be employed in a weight-loss routine," says Matheny. "There is a right way and a wrong way for each person depending on their current level of fitness and their goals. I still think a blend of the three is the best, but I do think strength training or strength combined with cardiovascular training can be more effective in a shorter amount of time than just cardiovascular activity. The reason for this is that cardiovascular training does not typically build lean muscle mass, which is key for increasing metabolism and helps burn more calories and aids in weight loss."

But above all, Matheny says, proper nutrition is key. "Exercise is important for so many reasons, but changing your nutrition can be the only thing you need to do if your goal is just weight loss," he says. "Any sort of exercise will aid in weight loss, but making sure you're nourishing your body properly is by far the most important thing you can do."

Interested in the cardio/weight-loss connection? Here are four reasons cardio might be sabotaging your fitness goals.

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