Bad news for fitness tracker companies. It remains unclear whether wearable technology actually affects weight loss, according to a new study published in The Journal of the American Medical Association (JAMA).

In the paper, Effect of Wearable Technology Combined With a Lifestyle Intervention on Long-term Weight Loss, researchers found through a randomized clinical trial that “effective long-term treatments are needed to address the obesity epidemic…(and) Numerous wearable technologies specific to physical activity and diet are available, but it is unclear if these are effective at improving weight loss.”

Different methods of behavioral weight loss intervention were tested against one another, with 471 adults participating between October 2010 and 2012 (data collection completed December 2014).

Participants were placed on a low-calorie diet, prescribed increased physical activity and had group counseling sessions. After six months, telephone counseling sessions, text message prompts and access to study materials on a website were added for participants. At six months, participants randomized to the standard intervention group initiated self-monitoring of diet and physical activity using a website, and those randomized to the enhanced intervention group were provided with a wearable device and accompanying web interface to monitor diet and physical activity.

Tracked over two years, the change in weight between both weight intervention method groups were compared, along with body compositions, fitness and dietary intake.

Weight change at 24 months differed significantly by intervention group, with estimated mean weight loss at 3.5 kg in the enhanced intervention group and 5.9 kg in the standard intervention group, a difference of 2.4 kg.

This means the addition of a wearable technology device to a standard behavioral intervention resulted in less weight loss over 24 months, but both groups had significant improvements in body composition, fitness, physical activity and diet, with no significant difference between groups.