IIf you’re using a fitness tracker at home or in the gym — or even just a fitness machine — what’s the most compelling metric it shows? In most cases, it’s probably an estimate of the calories you’ve burned. In fact, on most devices, you can’t disable calorie counting even if you wanted to.
However, these estimates are notoriously inaccurate: A Stanford University School of Medicine study compared seven different wrist-worn fitness trackers and found most Accurate estimates of energy expenditure, or calories burned, dropped by 27 percent. The least accurate is a whopping 93% off. None of the devices provided estimates of energy consumption “within an acceptable margin of error,” the researchers concluded.
It shouldn’t surprise anyone who knows the truth about calorie counting. Food labels that tell you how many calories are in packaged foods? These are also very unreliable because the averages they rely on don’t actually take into account how our bodies digest different foods. However, they are closer than calorie burn estimates: the FDA only allows up to 20 percent inaccuracy.
So, if these numbers are essentially meaningless, how do we accept them as a standard? Why do they have such a lasting impact on every new fitness tech that seems to be launched?
How calorie counting takes over our brains
Calorie counting dates back to the 1800s, which is very strange. Calories have been around as a measure of energy since the 1820s, but it wasn’t originally used to measure anything in the human body. That said, it wasn’t until 1896 that a researcher named Wilbur O. Atwater put a graduate student into a calorimeter, a device designed to measure the energy produced by explosives and engines. The machine measured everything the student ate and his energy output, showing that the human body absorbs and releases energy like a machine or bomb (oops).
However, calorie counting for weight loss didn’t catch on until decades later.This happened in 1918, when physician and newspaper columnist Lulu Hunt Peters published a book titled Diet and Health: The Key to Calories.
Needless to say, our understanding of the human body has come a long way since 1918.For example, we know that the nutritional value of food goes far beyond simply estimating how many calories you eat possible absorb from it. The many health benefits of exercise don’t just boil down to one number.
“People need to understand that these calorie counters are built on algorithms, and your body is not an algorithm. Your body needs certain things that other bodies don’t,” said Kerry O’Grady, national health liaison for the National Eating Disorders Association. . Different bodies absorb and burn calories differently (obviously, it takes more than just calories). “The more we believe the numbers, the more we stop listening to our bodies.”
“Calorie counters are built on algorithms, and your body is not an algorithm.” – Cleo Grady
For her, it’s personal. “That’s how I live,” she said. “I nearly died of anorexia in my 20s. I couldn’t use the tracker because it was so stimulating for me.”
This is not uncommon. Experts generally advise anyone with an eating disorder, loss of appetite or obsessive habit of exercise and nutrition to avoid fitness trackers. Even those without such a history may find trackers make healthy habits less satisfying. “Quantifying everything takes a lot of the fun out of exercise and food,” says personal trainer Lauren Pak. “It makes exercising and eating feel clinical, like a job.”
Some of us can look at calorie counts and ignore them, but many are affected more than they realize. “I think the hardest part about breaking the calorie count is that many of us may stop tracking, but calorie data is free in our brains,” says Jessi Haggerty of RDN, certified intuitive eating consultant and personal trainer . For example, if you feel like you’re not allowed to “indulge” on certain foods on your non-exercise days, you may not have worked out the exact math, but you’re still thinking about nutrition and exercise in a way that’s formed through calorie counting.
Do you know how many calories you need in a day? That could be wrong, says physical therapist, athletic performance coach and competitive weightlifter Rena Eleázar. “Almost across the board, the athletes I work with have a false sense of how many calories they’re consuming, and they’re often under-eating,” she said.
Wearables and connected devices can help some people maintain their exercise routine and remind them of their goals. Some data collected by trackers may be helpful. For example, heart rate information can help highlight exercise intensity and monitor the safety of some people with chronic diseases. Other measures, such as heart rate variability, can provide you with useful information about how you are managing stress both physically and mentally.
But the ubiquitous calorie counts on fitness trackers make food culture hard to shake off. “What works and what doesn’t is very personal,” Pak said. “You should be able to choose what you want to track. People shouldn’t assume that people tie weight loss goals to fitness activities.” With some systems, you can basically eliminate calorie counts by not entering your weight; others still do it by automatically replacing” Average” weight to show (even more false) calorie counts.
Calorie counting isn’t a good way to know what your body needs at all, and can lead you to limit what you eat in a way that can quickly become unhealthy, Hagerty says. The only situation where tracking calories might be useful is in people who struggle to eat enough to keep up with training, a common problem for endurance athletes, she said. “Even so, there are methods that don’t require tracking,” she said. If you’re unsure of what or how much you need to eat, Haggerty recommends working with a dietitian that is consistent with each size for Anti-Diet or Healthy. For those who train hard, a good rule of thumb is to eat three meals and three snacks a day, and eat within an hour of working out, she says.
So why do digital devices still contain calories?
Most of the digital fitness companies contacted for this story did not want to comment on the records, although some confirmed they did see consumer demand for calorie burn estimates. “They’re everywhere because people want them,” O’Grady said. “If the market didn’t ask for them, they wouldn’t exist. Even though a lot of people knew the numbers weren’t accurate, they would be upset if they were removed. That’s what these tech companies are counting on. They want you and that number to have relation.”
Food culture is so ingrained in many of us that we can’t mentally separate calories from exercise — even if we know better.
So, does that mean you need to break up with your fitness tracker? If you find yourself focusing more on the numbers on the screen than your body actually feels, maybe. “You can pretty much gauge your nutritional status based on how you feel at the gym,” says Eleázar. If you feel exhausted with every workout, it’s a sign that something needs to change, and you’ll most likely need to eat more. Trust how you feel about your body better than any tracker.
Even if you start tracking your workouts, don’t underestimate the benefits of simulation. For example, you can always use an old-fashioned pedometer to count steps, or a stopwatch to keep time. “I think it’s great to just write down your workout details,” says Pak. “Then you can track your progress each week. Maybe this week you do three sets of 10 squats with 25 pounds, and the next week you do three sets of 10 squats with 30 pounds. That’s a big improvement.”
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