Why your fitness tracker may not be your friend

A large-scale weight loss study, just published in JAMA, the journal of the American Medical Association, raises questions about how fitness trackers influence weight loss and eating behavior.

It found that over a 24 month period, people who did NOT use a fitness tracker lost nearly TWICE as much weight as the people who were assigned to use a fitness tracker. That’s right — the people armed with fitness trackers lost less weight than the people armed with a paper notebook.

The study followed 470 people aged 18 to 35 over a 2-year period. They all followed the same diet and exercise plan for the first 6 months, then were equally split into fitness tracker and non-tracker groups. The non-tracker group used a paper notebook to record exercise. The people who used a high-tech fitness tracker lost only about half as much weight after 24 months, despite engaging in similar levels of exercise — an average of 7.7 pounds vs 13 pounds.

Admittedly, 13 pounds in 2 years is not a great result, but 7.7 pounds after 2 years of effort is downright disappointing.

When asked to elaborate on the study, John Jakicic, a researcher at the University of Pittsburgh and the lead author on the study, said “These technologies are focused on physical activity, like taking steps and getting your heart rate up. People would say, ‘Oh, I exercised a lot today, now I can eat more.’ And they might eat more than they otherwise would have.”

It’s also possible, he says, that meeting daily fitness goals and step counts might motivate one person, but missing those same goals could discourage another.

We also know that fitness trackers can overestimate calories burned, and fail to take into account the user’s resting burn rate, which can trick the wearer into thinking they burned many more calories than they actually did.

We also consulted Dr Susan Roberts, author of the iDiet program, who says “The widespread belief that exercise and step-counting is essential for weight loss been remarkably resistant to debunking by science. Many intervention studies have shown that increasing activity has only a tiny effect on weight loss, and this JAMA study suggests that fitness trackers reduce the effect further. When programs over-emphasize the importance of physical activity, it can backfire by detracting from the critically important job of improving food habits.”

At iDiet, we focus on food first, and do not require exercise for weight loss. Moderate exercise is important for overall health and longevity, but studies show relying on exercise to burn calories often backfires by increasing hunger and creating a virtuous illusion that the burned calories need to be replenished — often at a higher level than were burned, and sometimes as indulgent food that increases hunger and cravings the next day. We also find that once iDieters start losing weight, they naturally become more active because they feel better and look better. This is a more pleasant way to reach health your goals, compared to feeling like exercise is penance for past mistakes.

So go ahead and track your steps if you like, but don’t rely too heavily on this data in your weight loss plan. Effective weight loss begins in the kitchen. You can eat delicious and healthy food, and treat physical activity as a condiment rather than the main course.

If you’d like to lose an average of 2 pounds a week, without hunger or gym time, why not sign up for our email list or explore our offerings here?