Preliminary Examination of an Innovative mHealth-Based Dietary Fiber Intervention to Improve Outcomes in Young Adults With Prediabetes: Protocol for a Single-Arm Feasibility Study.

BACKGROUND: One in 4 young adults has prediabetes, and improving diet is a key step to lowering the risk of diabetes. Existing standard-of-care diet approaches show short-term efficacy but lack long-term effectiveness, including in young adults. Greater fiber intake is associated with a reduced risk of diabetes; however, fiber is not well targeted using existing interventions. Many young adults may be reluctant to consume fiber given the coexistence with digestible carbohydrates and concerns over gastrointestinal effects. Targeting these factors more explicitly may improve uptake and lower diabetes risk, and doing so via a mobile health (mHealth) intervention may be particularly responsive to young adult demands. OBJECTIVE: This study aims to establish and preliminarily test the feasibility of a highly innovative and scalable mHealth-based intervention to improve fiber intake among young adults with prediabetes. METHODS: This single-arm feasibility study includes 2 phases to preliminarily test an mHealth-based fiber intervention (phase 1) and elucidate factors that impact sustained behavior change and fiber intake after intervention end using ecological momentary assessment (EMA; phase 2). The intervention is 3 months in length and features daily EMAs with responsive text-based coping messages to target key predictors of fiber intake. EMAs will also be paired with brief (ie, <1 minute) educational videos on fiber delivered once per day. Participants will also receive weekly home-delivered high-fiber food packages and wear a continuous glucose monitor at 2 time points during the intervention as a form of biofeedback. At the baseline and postintervention time points, fasting blood glucose, hemoglobin A1c, and insulin resistance (Homeostatic Model Assessment of Insulin Resistance) will be assessed. After the postintervention time point, participants will continue with daily EMAs to assess factors associated with sustained fiber intake. Diet will be assessed using Automated Self-Administered 24-hour dietary recalls at the baseline and postintervention time point and after the phase 2 EMA. RESULTS: This study was initiated in July 2025. As of March 2026, the mHealth intervention content is being built, with app completion and trial enrollment both slated to begin in April 2026. CONCLUSIONS: The results of this study will provide pivotal evidence on the utility of a fiber-focused intervention delivered via mHealth with biofeedback and home-delivered foods to lower the risk of diabetes in young adults with prediabetes.