Two in five U.S. adults have obesity, and up to 30% of treatment-seeking adults with obesity engage in binge
eating, an eating disorder behavior characterized by eating a large amount of food and experiencing a loss of
control while eating. First-line interventions are face-to-face treatments, but current approaches commonly fail
to address both conditions and cannot reach all people in need. To fill this gap, we designed FoodSteps, the
first intervention for both obesity and binge eating, delivered by mobile device to increase scalability. We
integrated key mechanisms of behavioral and psychological treatments to provide a personalized medicine
approach that intervenes on five evidence-based treatment targets. Each week, users select a target and
create a plan for how they will practice that target to change their behavior. Our pilot data show FoodSteps is
engaging with high rates of completion and compliance, and intervening on the targets improves weekly binge
eating and weight on average, but rates are suboptimal. Our data indicate more precise intervention is needed,
but three challenges impede achieving this goal. It is unknown 1) which evidence-based targets are most
impactful for which people; and 2) in what sequence; as well as 3) how best to deliver targets to propel users to
change their behavior. We will resolve these challenges with a micro-randomized trial, the methodologically
ideal design because it uses repeated randomization to inform how to precisely intervene based on individual
needs. Adults with obesity and recurrent binge eating will receive FoodSteps for 16 weeks. Each week, 1 of the
5 targets will be randomly delivered to each user, to identify which targets work for whom (Aim 1) and in what
sequence (Aim 2). Weekly targets also will be randomly delivered either as a recommended target users can
select or as an assigned target, to identify how to deliver targets to propel behavior change (Aim 3). We will
assess time-varying user characteristics as moderators to inform the development of personalized algorithms
to tailor interventions to user needs over time. Our outcomes of interest are weekly changes in binge eating,
since it is a behavior that puts overall weight loss at risk, and change in weight long-term (Aim 4). Our data will
provide the infrastructure to build a just-in-time adaptive intervention (JITAI) capable of delivering highly
personalized intervention for binge eating and weight-related behaviors at a critical point in the behavior
change process; we will test the JITAI in a future trial. This trial furthers NIH and NIDDK’s mission to advance
treatment via more precise approaches by specifying which treatment targets drive behavior change, led by a
team expert in optimizing digital interventions, intervening on obesity and binge eating, and conducting micro-
randomized trials. Results have implications beyond FoodSteps given the role of these targets and processes
for behavior change broadly, and will propel personalized medicine by informing sophisticated models for
achieving the ultimate goal of personalizing the delivery of digital and non-digital interventions.
