Weight loss in Weight Watchers Online with and without an activity tracking device compared to control: A randomized trial

WWO produced significantly more weight loss at 3 months relative to Control, but not at 12 months. Significantly more WWO than Control participants lost ≥ 5% at both 3 and 12 months. Participants receiving an activity tracking device did not achieve greater weight loss or physical activity increases than those in a Control condition.