The purpose of this pilot study is to examine the effects of different types of just-in-time intervention messages on daily meeting dietary, activity, and weighing goals in a sample of young adults participating in a mobile-based weight loss program.
Public health interventions typically rely on a set schedule of intervention delivery. Advances in technology and computer tailoring allow us to go from a "one size fits all" approach to one that uses digital health data to deliver "just-in-time adaptive interventions," or JITAIs, that can vary the timing, dose, and content of intervention messages to individuals. This pilot study is a micro-randomized trial that evaluates the effects of various intervention message options delivered in JIT moments on meeting dietary, activity, and weighing goals among young adults in a mobile-based weight loss program. The Nudge study is a 12-week mobile health weight loss program delivered via a native smartphone application. Individuals are asked to track their red foods (high-calorie, high-fat foods) in the app daily and meet their personalized red foods goal, wear a Fitbit daily and meet their daily active minutes goal, and weigh daily on their WiFi-enabled scale. Up to 4 times each day, participants are randomized to receive or not receive intervention messages in order to examine the effects of these intervention message types on meeting daily weighing goals, red food goals, and activity goals. This is a within-subjects design in which each participant serves as their own control, and data is analyzed at the person-day level.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
53
Nudge is a smartphone-app-based micro-randomized trial that tests the effect of 7 intervention message types based on behavior change techniques on daily goal attainment. Participants have three daily goals: weigh daily, red foods goal, and active minutes goal.
Department of Health Behavior, University of North Carolina, Chapel Hill
Chapel Hill, North Carolina, United States
Percent of person-days with same-day weighing
Percent who weighed after the message randomization time until the end of the day (at the participant-day level) across the 12-week study
Time frame: from Baseline to Week 12
Percent of person-days with next-day weighing
Percent who weighed the day after the message randomization (at the participant-day level) across the 12-week study
Time frame: from Baseline to Week 12
Percent of person-days met active minutes goal on same day
Percent who met active minutes goal after the message randomization time until the end of the day (at the participant-day level) across the 12-week study
Time frame: from Baseline to Week 12
Percent of person-days met active minutes goal on next day
Percent who met active minutes goal the day after the message randomization (at the participant-day level) across the 12-week study
Time frame: from Baseline to Week 12
Percent of person-days met red foods goal on same day
Percent who met red foods goal after the message randomization time until the end of the day (at the participant-day level) across the 12-week study
Time frame: from Baseline to Week 12
Percent of person-days met red foods goal on next day
Percent who met red foods goal the day after the message randomization (at the participant-day level) across the 12-week study
Time frame: from Baseline to Week 12
Number of active minutes
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Total number of active minutes on the day of message randomization (at the participant-day level) across the 12-week study
Time frame: from Baseline to Week 12
Proximal effect of message on total red foods today
Total number of red foods on the day of message randomization (at the participant-day level) across the 12-week study
Time frame: from Baseline to Week 12
Mean weight change
Mean weight change across participants
Time frame: from Baseline to Week 12