Abstract Body (Do not enter title and authors here): Introduction: Self-monitoring (SM) lifestyle behaviors is the cornerstone of behavioral treatment for weight loss, but adherence declines. Mobile health (mHealth) tools can lessen the burden of SM and enable timely feedback (FB) to reinforce SM behaviors.
Hypothesis: A greater number of FB messages received will be associated with better adherence to diet, physical activity (PA), and weight SM and study-prescribed diet and PA goals.
Aims: To examine the association between adherence to diet, PA, and weight SM and calorie, fat and PA goals and the amount of FB received for participants assigned to the SM+FB arm in SMARTER, a 12-month mHealth weight loss clinical trial.
Methods: We randomized 502 participants to either SM+FB or SM alone and asked them to self-monitor diet via the Fitbit app, PA via the Fitbit tracker and weight via a smart scale over 12 months. Participants recorded food intake and tracked PA daily and self-weighed at least weekly. Using SM data uploaded in real-time, the SM+FB group received 3 tailored FB messages daily on their study-designed smartphone app (daily for diet, every other day for PA, weekly for weight). We applied generalized linear mixed-effects modeling to examine the association between the number of FB messages opened and adherence to SM and to study-prescribed goals analyzed as a percentage or meeting the threshold and reported as the unstandardized regression coefficient (b) or odds ratio (OR) with 95% confidence interval (CI) and p-value.
Results: The SM+FB group (n=251) was 84% white and 80% female with a mean age of 45.0±14.3 years and a mean BMI of 33.7±3.9 kg/m². Over 12 months, the SM+FB group opened a mean 471.3±279.7 FB messages. While adherence to diet, PA, and weight SM and to diet (calorie and fat) and PA (weekly minutes) goals declined nonlinearly (p<.05) over 12 months, the number of FB messages received was positively associated with SM and goal adherence: daily diet SM (OR=2.61, 95%CI=[2.46, 2.76]; p<.001), daily PA SM (OR=3.04, [2.72, 3.40]; p<.001), weekly weight SM (b=2.03, [1.90, 2.16]; p<.001), daily calorie goals (b=2.21, [1.95, 2.47]; p<.001), daily fat goals (square root transformed) (b=0.17, [0.14, 0.19]; p<.001), and weekly PA goals (b=5.22, [3.49, 6.95]; p<.001).
Conclusion: Providing feedback to participants reduced the decline in adherence to SM and lifestyle change goals; however, additional strategies are needed to enhance long-term engagement with mHealth tools and improve weight loss outcomes.