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Why it's time to stop listening to your fitness tracker

If you're measuring calorie burn using a wearable heart rate monitor and fitness tracker, the calorie feedback may be way off.
/ Source: NBC News

Think you torched 500 calories during spin class? You may have to think again. New research from Stanford University and the Swedish School of Sport and Health Sciences found that if you're measuring calorie burn using a wearable heart rate monitor and fitness tracker — such as the Apple Watch or Fitbit Surge — the calorie feedback may be way off.

Though six of the seven devices tested produced accurate heart rate readings (within 5 percent), even the most accurate tracker was off by an average of 27 percent when it came to measuring energy expenditure. The worst was off by 93 percent!

To put this more simply, if your device suggests you've moved your way through 2,200 calories, on the low end it could be overestimating by as many as 600 calories.

"The error depends on the type of activity you're tracking," said lead study author Anna Scherbina, "For activities like walking and sitting, the results are more accurate than for more intense pursuits, like spinning and running," she explains. "The point is, you're not burning as much as you think you are."

The problem with calorie math

Clearly this study highlights one problem with the calories in vs. calories out equation. Even when you're using a tech gadget to track calories out, the results are likely too high to tie to the amount you should or can consume. Even those of us who aren't math whizzes can see how this could stall weight loss or even worse, lead to gain, despite your best fitness efforts.

Other studies have shown that calorie counters on cardio machines — treadmills, elliptical trainers — are also overstated. Machines don't take into account your fitness level or whether you're leaning on the handle bars or doing something else that makes a workout easier — things that ultimately impact calorie burn.

Still more research shows that people under-report how much they eat, and for those who have been obese or lost a significant weight, metabolism changes alter the equation.

A better way to think about calories

None of this is to say that you shouldn't track calories or think about them at all. I'm in favor of being calorie aware — recognizing calories that work hard to fill you up, nourish your body and energize your day-to-day marathon of life. Those calories come from whole food, like fruits, veggies, whole grains, nuts, seeds, beans and quality sources of protein, like sustainably-raised seafood and hormone- and antibiotic-free meats and poultry.

Calories from things like sugary and refined carbohydrates — like candy, cookies and white breads, crackers and cereals — don't provide the same benefit, even if the numbers are the same. Beyond being calorie aware, there are some powerful ways to help you manage your food intake and more closely match it to your individual needs.

Become more mindful

The practice of intuitive eating rejects the notion of calorie counting and encourages a more conscious practice of tuning in to your body to assess when it's hungry and when it's satisfied. Similar to meditation, this practice focuses on the act of being present while you're eating (turning off the TV, putting down the phone, giving email a break), so you can fully experience the sensation. Mindfulness techniques can also help you manage stress, which can reduce cortisol levels and may lead to a reduction in belly fat over time.

Minimize mindless eating

There are an enormous number of environmental cues that lead us to eat, and possibly overeat. Sometimes these elements are beyond your control, such as big portions at restaurants, junk food at a checkout counter or the candy dish at the reception desk. Though you may not be able to change your environment, let's be clear: Information is power. Recognizing that these environmental cues trip you up is the first step toward gaining control of your personal food environment.

Using smaller plates and ordering appetizer portions is one way to manage the amount you eat without obsessing over calories. Placing less healthy foods out of sight is another great strategy. If your cookie jar is on the counter, tuck it away. (Or replace the cookies with whole grain crackers or nuts.) Buying single-serve treats is another great way to go. Simply seeing the wrapper can help you pause before you go back for more. Notably, this was shown in a study on pistachios. People who snacked on nuts in the shell and left the shells around as a visual cue consumed 41 percent fewer calories — yet reported the same level of fullness —as those who snacked on shelled ones.

Mange social and emotional situations

We eat not just to end a nagging hunger pang or give our bodies nutrients, but for social reasons like happy hour, client dinners, catching up with friends and the like. And then there are the emotional reasons: Anger, stress, boredom, sadness and anxiety can all point you in the direction of the kitchen.

To get a handle on calorie intake, it's important to get a handle on these situations, too. I don't want to rob you of the joys of your social life, but if restaurant meals are more than an every-so-often affair, take note of how you could eat better in those situations. Maybe you could order more veggies or split an entrée with a friend. Perhaps you could pass on dessert, and tell your dining companions, "I just had ice cream cake over the weekend so I think I'll pass tonight."

To break the emotional eating cycle, it helps to take note of what's going on so you can respond appropriately. I always remind people that food doesn't settle an argument, ease your workload or provide any emotional support whatsoever. Think about ways to boost your mood instead. Play a favorite song, call your best friend, go for a walk or read a trashy magazine. I'm a fan of meditating so add this to your list of things to try. Figure out what works for you and stick with non-food ways to soothe your soul.

Keep track of what you eat, too

For people who need accountability, I'm in favor of using an app to track what you eat. A free downloadable food diary, such as Lose It! makes it easy to spot patterns and notice when you're running into trouble — say, a daily afternoon stop for M&Ms or a routine bagel breakfast.

Tracking can also add an element of mindfulness. Just knowing that you have to input what you eat may allow you to push the pause button and think for a moment about whether it's worth it. And seeing that a handful of pretzels can set you back 100 calories might help you pass them up, particularly in light of the fact that you're probably not burning as many calories as you think you are.

And if you still enjoy the feedback from a wearable device, note that Apple Watch had the most accurate readings. Making sure you have a snug fit may also improve accuracy. "You need good contact with your skin," said Scherbina. But perhaps think twice before gifting a tracker to the man in your life. "Though the calorie burn was inaccurate for everyone, it was worse for men than women," she noted.


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This story was originally published on NBC News BETTER.