Take a quick glance around any crowd and you’ll see a number of people sporting rubber wristbands. These bracelets fall into the category of “wearable technology,” the most common type being a fitness tracker - like a Fitbit.

These trackers collect data on your physical activity, diet, and health. Information on number of steps taken, heart rate, sleep quality, and other measurements let you optimize your daily habits. This is done with the goal of better health – and often weight loss – in mind.

Many hardcore users track their numbers in charts on the manufacturers’ websites. They use this feature so they can keep trends moving in the right direction. Plus, they often participate in online communities for the purpose of encouragement and competition.

But sadly, for avid fitness trackers, new research in the Journal of the American Medical Association found that wearable tech doesn’t help its users lose weight.

As studies go, this was a good one. Participants were given counseling, prescribed physical activity, and placed on a low-calories diet. After six months, telephone counseling, text messaging, and access to educational materials were added to the program. The 471 subjects were then randomly assigned to two groups. The first group was asked to self-initiate tracking of diet and exercise on a website. The second group was given a fitness tracker that was connected to a web interface.

Two years went by, and researchers compared the weight of the two groups. The wearable device group lost 3.5 kilograms. That’s not terrible, but the group that had to manually track their progress on a website lost 5.9 kilograms.

So save your money. Fitness trackers don’t work. Right?

Well, maybe. Or maybe not. We have to look at what the study doesn’t tell us.

Usually we start with correlation – “Oh, we noticed these people with fitness trackers don’t seem to be losing weight like their friends without. Let’s do a randomized trial to see if the fitness tracker is the problem.” Then we take that correlation, or association, and study it specifically with a prospective, randomized trial to see if there is causation.

To determine causation, we like to make the study groups’ circumstances as similar to one another as possible. This study accomplished this by having both groups engaged in intensive behavioral intervention.

So now we know that, in the setting of intensive behavioral intervention, fitness trackers don’t aid weight loss.

But most of us don’t start a weight loss plan with the assistance of counseling and medically prescribed diet and exercise plans. We lace up our shoes and go for a run. We try to cut down on our food intake. We stop eating the crusts we cut from the kids’ sandwiches. Some of us are more engaged and serious about the process than others – it all comes down to our own intentions. But in the study, established methods of behavioral change helped prop up those intentions.

In real life, if you don’t have these outside factors helping you maintain your focus, the Fitbit might help – a little or a lot or not at all – we can’t say because the study didn’t address this question. But in this study the Fitbit was redundant at best.

We also must consider how personality comes into play. Avid users, like Scott Burns, who enjoys manipulating numbers more than is usual, and David Sedaris, a self-described obsessive, may not lose weight because of the Fitbit. But the Fitbit works with the constellation of behaviors that do help them lose or maintain weight.

So, if you are a techie, don’t stress too much about this study. It may not be necessary to obsess about your numbers so much, but if it’s working for you, carry on. On the flipside, if you don’t like tech gadgets and just want to enjoy your daily run without obsessing over it, you probably aren’t missing out on anything. The key here is to do as the Greeks suggested: Know Thyself.

Amy Rogers MD is not a practicing physician and nothing written here should be taken as medical advice from either Amy or AssetBuilder. Medical decisions should be made with care in consultation with your health care provider.