Why Your Fitness Tracker Can Be Making You Fat
July 7, 2015

Are fitness trackers a terrific investment and worthy of your hard earned cheddar, or are they actually doing you a disservice, and could even be making you fat?

In the ever-growing tech world that we are currently living in, the latest and greatest gadget is something called wearable technology. This is becoming increasingly popular in the health and fitness industry, with fitness trackers you can purchase, designed to keep track of how active you are, how many calories you’re burning, and if you’re living a healthy lifestyle.

A few days ago one of my colleagues came over and wanted to pick my brain about living a healthier and more active lifestyle. His main concern was which fitness tracker he should use, or if it was even worth it. As I was asking him some questions I learned that Nike had decided to discontinue their FuelBand, a device that I remember used to be all the rage.

In theory, these fitness trackers sound like a terrific investment. However, after some research, it quickly becomes apparent that not only are they not worthy of your hard earned cheddar, they might actually be doing those that own them a disservice, and could even be making you fat.

Iowa State kinesiology professor Gregory Welk, who participated in a recent study by the American College of Sports Medicine on the accuracy of fitness trackers opined “people buy these activity monitors assuming they work, but some of them are not that accurate or have never been tested before…just produce a nice-looking device with a fancy display, and people buy it.” I uncovered some glaring issues with these well intentioned yet over marketed, underperforming products.

Not All Calories are Created Equal

Calories, calories, calories. The common man’s weight loss arch nemesis. All you ever hear about is the importance of calories. “How many calories are in that? Oh okay, yeah I’ll take a pass, that’s way too many.” “I drink diet coke because it has less calories, it’s better for you.” Does anybody actually know what a calorie is? It’s a unit of energy, needed for your body to carry out its’ biological functions, needed for you to get up in the morning, needed for your brain to function properly, needed for you to build the life that you dream of. But all we ever hear about is the bad side of calories, because too many of them can cause a host of health problems.

Type

What you might not know, however, is that the right amount can still cause these same issues, especially when it comes to your quest to lose weight, reduce your disease risk factors, and look better naked. The prevailing wisdom is that it’s all about energy balance-calories in versus calories out. WELL, that’s not entirely true. Not all calories are created equal. There’s a little something called the thermic effect of energy that governs how those calories are going to be used within your body. All else equal, your body burns about 25% of the energy value of 1G of protein when converting it into usable energy, about 10% for 1G of carbohydrate, and somewhere between 2-5% for 1g of fat. So as you can see, where you are getting your calories from is important in weight loss.

Not all calories are created equal. There’s a little something called the thermic effect of energy that governs how those calories are going to be used within your body. All else equal, your body burns about 25% of the energy value of 1G of protein when converting it into usable energy, about 10% for 1G of carbohydrate, and somewhere between 2-5% for 1g of fat. So as you can see, where you are getting your calories from is important in weight loss.

Timing

Timing is also very important, especially when it comes to carbs. “CARBS ARE THE ENEMY! THEY’LL MAKE YOU FAT!” By now, I’m sure you’ve heard these claims. This isn’t entirely true. Let’s use bananas as an example as to why the timing of when you eat the carbs is the most important factor in how your body uses them. Glucose, or simple sugar, is what a carbohydrate breaks down into and is your body’s and brain’s main source of energy. It’s actually your brains only source of energy. So let’s say you wake up in the morning and have a banana for breakfast at 8AM. The carbs from the banana will be used by the cells in your body- used to think, used to do work, used to make things happen. In this case, carbs are a good thing, you absolutely need them.

Now, let’s say you eat that same banana at 8PM. You probably are not doing much besides for Netflixing the rest of the night and don’t really need any energy. Your cells will then convert that glucose into fat, a form of stored energy, until you really need it. So, let’s say you’re the average American and your dietary intake is between 1800-2400 calories. Where you get those calories from and when you consume them can make a large difference in whether you’re losing weight, or getting fatter.

Fitness Trackers are NOT Accurate

My biggest issue with fitness trackers is that they don’t even come close to possessing the right technology to consistently provide an accurate picture of how active you’re being on a daily basis. Let’s say you’re using your tracker to provide an estimate of your daily calorie expenditure and matching your caloric intake with this. Now, let’s assume that your tracker is off by 250 calories. A calorie surplus of 250 calories a day will lead to about 26 pounds in weight gain over the course of the year. Twenty six! The American Council on Exercise did some studies on the five most popular trackers, and had some interesting findings. According to Cedric Bryant, Ph.D.:

“There are certain assumptions that are made when developing the algorithms that translate movement activity detected by the devices into calories burned. Even devices with the best prediction equations will have some margin of error due to natural biological variability.”

The study found that the trackers were off by a minimum of 13 and up to 60 percent. As you can see from the chart comparing the calorie burn estimate from the four most popular fitness trackers, these devices are all over the place. So, if you’re using these trackers to help you lose weight, be aware of the documented shortcomings of these products. As WIRED reported in 2012,

“The only way to get an accurate read on calories burned is with an indirect calorimeter, which analyzes your oxygen consumption using a face mask and costs between $30,000 and $50,000.”

Another limitation to these devices is their ability to monitor sleep patterns. Fitness trackers don’t necessarily have the ability to distinguish between when you are awake versus when you’re asleep. This may lead to them giving false information. For example, let’s say you roll around in your sleep. A tracker could inaccurately account for this as movement, further derailing your attempts at monitoring your activity level.

Benefits

While it has been shown time and again that fitness trackers have some fundamental flaws, they can, when used properly, be useful tools to help motivate us to lead a healthier and more active lifestyle. For example, they can track relative movement, and have also been shown to give a reasonable estimate of steps taken. With this in mind, if you buy them to monitor your activity alone and understand that the nutrition side of it is equally, if not more important than exercise, purchasing one may be a great decision. If it makes you take the stairs, park your car further away, walk to work, get up and move around during your workday, then we all win. “These gadgets allow us, mere untrained mortals, to gauge what only doctors used to measure…by monitoring continuously, not once a year at a physical.” A year wondering how you’re doing no longer has to be followed by the proverbial smack in the face on January 1 when you realize your lifestyle has moved the needle 15 pounds in the wrong direction.

The Bottom Line

The fitness tracker is at best a cautionary tale in its’ infancy. There are many factors that go into your health and fitness beyond just counting steps. Everyone is different. According to Dana James, certified nutritionist and founder of Food Coach NYC, “if your gut bacteria is full of bad bacteria, you can eat 30 percent less calories, exercise 30 percent harder, and gain 30 percent more than someone with the right microbial makeup.” Before purchasing one of these devices, do your homework and understand its limitations and usefulness. Hopefully this will help you make an informed decision when deciding whether it’s worth spending $100 on something with good intentions yet limited capabilities.

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