What makes you pry yourself away from your comfy bed to hit that treadmill at the gym or push yourself after a long day at work to squeeze in a sweat-inducing spinning class? Sure, you want to be healthy, but if you’re truly being honest with yourself, chances are your top reason is to look good or to lose weight. In fact, weight management is the number one motivation for women to work out.

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And yet most of us fail to reach our weight loss goals, and end up right back where we started. So what gives?

The truth: We’ve been working out for the wrong reasons.Michelle Segar, Ph.D., associate director of the Sport, Health, and Activity Research and Policy Center for Women and Girls at the University of Michigan, has spent years studying the motivations people have for engaging in exercise. Segar’s research has found that working out to lose weight is actually one of the least successful ways of getting in shape.

It’s true that many of us should be concerned about our waistlines. According to the Centers for Disease Control, more than a third of Americans are obese and another 33.5 percent are overweight. Anyone with a BMI higher than 24.9 has an increased risk of diabetes, heart problems and a whole slew of other diseases. So it’s not surprising that so many of us focus on that (not so) little number on the scale and use it as our main motivation for exercising.

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But when it comes to losing weight, intensifying exercise simply isn’t that good of a strategy. “Understand that you can’t out-exercise your diet,” says Brynn Jinnett, founder of Refine Method, a New York-based exercise program heavily grounded in the science of fitness. She’s 100 percent right. Studies have found that increased daily exercise by itself produces moderate weight loss results at best.

When scientists asked men to work out for either 30 or 60 minutes a day, for example, they found that both groups lost weight when compared to a control group that didn’t work out at all, but doubling the exercise didn’t double the results. In fact, the guys who worked twice as hard lost the same amount of weight as those who made half the effort.

How can that be? Well, it turns out that our bodies tend to like to stick to the status quo. To lose weight, we have to use our fat reserves for energy, which means overall, we need to lower our calorie intake to expense ratio. But creating this negative energy balance triggers protective mechanisms meant to prevent starvation. Our bodies compensate for the missing calories by eating more or becoming more sedentary overall. That’s what happened to the men who worked out twice as hard—though they burned double the calories during their workouts, they ate more calories per day, which may explain why they lost less weight than expected.

The other downside of our tendency to equate exercise with weight loss is that we lose sight of how important exercise is for other reasons. Scientists have found that physical activity and exercise help keep our brains happy and healthy—a much better reason to work out five days a week. Exercising not only strengthens muscles, it also helps normalize and stabilize the neurotransmitters involved in mood and stress, thus improving overall mental health. Studies have found that working out even has a positive effect on all kinds of mental disorders from obsessive-compulsive disorder to substance abuse. In general, exercise decreases anxiety and depression, putting us in an overall happier state.

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Not only does working out not lead to as much weight loss as we’d like, slugging ourselves to the gym because we want to lose weight also decreases our desire to exercise. When it comes to physical activity, motivation matters more than you might think.

At Refine Method, Jinnett helps clients focus on what they really want to get results. “A vague desire to feel stronger will have less power than a clear commitment to build a stronger back so that you can lift your child safely,” she explains. “Goals that are well-defined, rooted in your values as a person and a bit too easy will have greater sticking power. We encourage our clients not to focus on losing five pounds, but rather to define clearly what ‘looking better’ means to them and understand why changes to their body composition are important to their greater goals and values.

”It’s more than just dialing in on specifics, though, says Segar. People with the right kind of motivation work out more regularly, enjoy their fitness activities more and get better results.Scientists have found that the more we focus on our weight or appearance, the less likely we are to succeed at our fitness goals. That’s because, for the most part, we focus on appearances to please others. Successful exercise motivations, on the other hand, are those that are intrinsic, focusing on benefits that are felt solely by the person performing the activity. These include reducing stress or enjoying a sport. Women with these intrinsic goals work out more often, stick to a routine and reap the most rewards, including lower overall body fat and improved health. In contrast, women who work out to lose weight or get fit—extrinsic motivators with the ultimate goal of impressing others—tend to be flakier about their workout regime, don’t exercise as often and tend to have higher BMIs and lower self-esteem.

In fact, Segar’s research found that middle-aged women who worked out because they wanted better quality of life—with immediate goals such as sleeping better or feeling centered—exercised 34 percent more than women with goals related to weight loss and appearance and 25 percent more than those whose goals were related to fitness and health.

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The way Segar sees it, exercise has a branding problem. “The specific socialization to exercise that individuals have had through the media, health care and society in general has explicitly branded exercise primarily as a vehicle that promotes ‘weight loss,’ ‘health benefits’ and ‘disease prevention,’” she and her colleagues explain. Those are all good things—but it also has created a culture where many people exercise because others tell us we have to, not because we actually want to. Without intrinsic motivation, we simply don’t work out as much as we know we should.Instead of distant, intangible motivations, such as preventing future disease, Segar suggests focusing on immediate benefits, such as increased energy, less stress or a better mood. “Start small,” she says. “You have your whole life to be active. Why not set yourself up for success instead of failure?”The more we focus inward on how exercise makes us feel—the happy buzz of endorphins or reduced stress—the more likely we are to stick to our workouts and get the results we want on all fronts. If you’re one of those people who tends to lose momentum or quit after a few months, here’s the real scoop: Don’t work out because you should or because you think you need to lose weight. Work out because it will make every day a little better. Work out because you have fun doing Zumba, like the peacefulness you feel during yoga, or love having time to think while you’re running or whatever it is you do to break a sweat.

Really, the key to success is to stop working out because of what other people might think or because you’re trying to achieve some unrealistic ideal body that no one can live up to. Exercise for yourself, and you’ll be surprised at just how easy it is to keep at it.

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