Activity trackers, often worn on the wrist or waist, are designed to encourage more movement throughout the day. And people who wear them do seem to be more physically active. However, these people don't necessarily lose more weight than others.

A group of scientists designed a study to test if activity trackers are helpful for weight loss and maintenance. Study participants received the same weight-loss counseling (diet, exercise and support) for six months and lost similar amounts of weight. After the initial six months, all participants received telephone counseling, text message prompts and access to online weight-loss information.

Some participants also received wearable devices and access to an accompanying website to monitor physical activity and diet. Both groups were able to maintain weight loss up to 24 months. However, the group with the wearable technology lost 2-3 percent less weight over the course of the study.

One possible explanation for this difference is that those wearing trackers chose to reward themselves for meeting exercise goals with dietary indulgence. In other words, if the tracker said they burned 400 calories or completed a certain amount of exercise, they might choose to eat dessert. This could lead to slower weight loss or even weight gain.

From this study, it appears that activity trackers aren't a guarantee of weight-loss success. So should you give up on your tracker? No. A tracker can be a useful tool for getting you to move more.

Here are some tips on how to make an activity tracker work for — and not against — your weight-loss goals:

• Use the tracker to get a baseline of your daily movement and then set a goal 2,000-3,000 steps higher.
• Use it as a motivational tool to encourage movement and as a historical record. If you have a bad day, you can look back and see that it was only one day among many good days. This perspective may keep you from falling off the wagon because of "all or nothing" thinking.
• Use the information from the tracker as a guide but not as permission to throw dietary discretion out the window.