Optimizing a standalone text messaging-based weight loss intervention
Novel and disseminable approaches are necessary to make a sustainable population-level impact in addressing the obesity epidemic. mHealth strategies like text messaging are particularly promising. However, despite mounting feasibility evidence, text messaging trials frequently report suboptimal weight loss outcomes. For these interventions to have population-level impact, we must make their outcomes more robust. The overarching goal of this proposed project proposal is to improve the outcomes of standalone text messaging obesity interventions. We focus on standalone approaches -- those that involve texting as the sole delivery channel -- because of their dissemination potential.
To accomplish this goal, we propose to use the multiphase optimization strategy (MOST) to conduct a 6-month experimental trial among 592 obese adults. MOST guides randomized experimentation of intervention components so that we might assemble a treatment package comprised of only active components. All participants will receive a core 6-month weight loss texting intervention (based on our iOTA approach) that includes tailored behavior change goals, interactive self-monitoring, automated feedback, and skills training. Using a fractional factorial design, we will randomize participants to one of 16 experimental conditions that will test the text messaging components (and levels). We will follow participants at months 1, 3 and 6. We will experimentally determine which text messaging components (and component levels) produce a meaningful contribution to 6-month weight change and 6-month change in diet, physical activity, and the proportion of participants who achieve > 5% weight loss. We will also examine potential mediators of weight change, including intervention engagement, self-efficacy, and perceived ease of use and usefulness and determine the cost of the intervention’s implementation and its incremental cost effectiveness.