Fitness trackers: What’s the verdict on behavior change?

Irrational Labs
4 min readOct 26, 2016

By Kristen Berman and Ingrid Melvaer Paulin | October 26, 2016

Fitness trackers have come a long way from the clunky and unreliable plastic devices they once were. Today’s versions are well-designed, more accessible and more accurate in tracking your steps than ever. They are also extremely popular, especially among the young and affluent. The market for wearables exceeded $2 billion in 2015, and is expected to hit almost 3 billion this year and over 4 billion in 2017. But do they actually help us get more active?

In order for fitness trackers to help shape our waistlines for the better, we’d have to make a few key assumptions about how and why they work.

Let’s review these key assumptions one by one to see if the the trackers are likely to increase our activity levels.

This assumption feels rather obvious but is a critical question to consider. Will you put on the device each morning? The device will struggle to impact your waistline if it sits in a drawer.

In a survey of 6223 Americans, researchers found that more than half of individuals who purchased a wearable device stop using it and, of these, one third did so before 6 months had passed.

A recent year-long study published in The Lancet Diabetes & Endocrinology, had the same issue: About 40% of research participants stopped using the tracker within the first six months, and by the end of the year a mere 10% of people were still wearing them. A big problem with fitness trackers is that it is difficult to get people to keep using them after the initial novelty has worn off.

Unfortunately, just increasing one’s knowledge of something is not that promising as a strategy for behavior change. Research suggests that this is the case in a wide area of domains, from financial literacy to information about calories. For example, there a wealth of information available on how many calories are in hamburgers or desserts, and while we know high-caloric foods will make us gain weight we still eat them.

A couple recent papers support that this may also be the case for fitness trackers. A September 2016 paper published in JAMA has shown that people who used fitness trackers as part of a weight loss program lost less weight than people who did not. As a potential caveat, it is important to note that this study was done with an old device rather than a modern tracker.

Another study, published at the beginning of October in The Lancet Diabetes & Endocrinology, showed that using a FitBit tracker only resulted in a small, insignificant boost to activity and did not significantly improve health outcomes. This was true even when participants were given a financial incentive to reach a weekly step goal.

Why is this? Behavioral science has shown in many domains, outside of health, that while having the facts is important, it is rarely enough to change our behavior. Behavioral scientists refers to this as the gap between action and intention.

Research about the gap between our intentions and actions suggests that just knowing you need 5000 more steps every day is not enough to get you to walk to work instead of taking the bus, or go for a 30 minute stroll after dinner instead of relaxing on the couch by the TV. To actually increase activity levels we would need to hack more deeply into our daily routines.

Think back to the last time you ate a salad for lunch and then fast forward to 3 PM. At 3 PM, you may have been hungrier than usual. Did you give yourself permission to grab a less healthy snack because you were so ‘good’ at lunch and had a salad? This is called the licensing effect, and it can cause interventions to backfire when people overcompensate for their good behavior by indulging in something less good.

When we feel great about reaching our step goals, we often celebrate by treating ourselves to a more unhealthy meal or an extra snack. This can add up in the long run, outweighing the positive effects of the small boost in activity.

Similarly, tracking may also change the nature of how we think about our fitness activities. Instead of it being a pastime we do out of pure enjoyment, it may start to feel like work. A study by Jordan Etkin from Duke University’s Fuqua School of Business found that measuring an activity can make us enjoy the activity less and do less once we stop tracking it. By focusing on the outcomes of things that used to be fun, enjoyable activities can become almost like a job.

So far, the research shows that when fitness trackers do help us get more active, it is usually because they are used in combination with other behavioral interventions. These interventions do not need to be complicated:

In 2015, the fitness tracker Jawbone introduced a feature called Duels to their app “UP” which applied the principle of adding a social element to engage users. Duels allow participants to challenge one or more friends to a competition where whoever has the most steps after a set period wins. The company replicated findings from behavioral science showing that the more people we exercise with, the more active we are: In fact, those who have just two teammates in the app move, on average, 7% more than those who use the step counters alone.

Originally published at on October 26, 2016.



Irrational Labs

Irrational Labs is a product design company that creates behavioral change for good.