Optimizing a Weight Neutral Intervention to Improve Health Among Adults of Higher Body Weight: A MOST Preparation Phase Study

Project Summary Obesity remains a major public health concern and is a leading contributor to cardiometabolic disease. Frontline treatments aim to directly facilitate weight loss, but outcomes are variable and difficult to sustain. Weight neutral approaches are gaining scientific, clinical, and public attention as an alternative pathway to reducing cardiometabolic risk for individuals of higher body weight. These programs support improved quality of dietary intake and engagement with physical activity without encouraging weight loss, and target novel ‘weight neutral’ mechanisms to support adherence over time (e.g., eating in response to hunger/satiety cues, disengaging from rigid rules about food, increased body appreciation, combating weight-related stigma, and promoting physical activity for enjoyment.) Despite growing interest, efficacy for weight neutral interventions on cardiometabolic health, along with the generalizability, scalability, and sustainability of treatment effects is not established. Additionally, there is significant variability in how the weight neutral programs are designed (i.e., which weight neutral mechanisms are targeted and how), leaving it unclear which weight neutral mechanisms meaningfully contribute to treatment effects. The goal of this R03 is to use the Multiphase Optimization Strategy (MOST) to build a clearly defined weight neutral intervention that effectively targets the weight neutral mechanisms that are central to this therapeutic approach. Candidate weight neutral components will include the following existing, evidence-based interventions with demonstrated effects on weight neutral mechanisms; (1) mindfulness-based eating awareness training (mechanisms: to increase eating in response to hunger/satiety cues and reduce rigid dietary restraint), (2) body acceptance program (mechanisms: to improve body appreciation and reduce internalized weight-related bias), and (3) a tailored intervention to promote enjoyment of physical activity (mechanism: enjoyment of physical activity). Weight neutral components will complement a Core intervention of standardized education on healthy diet (emphasizing the Mediterranean diet) and Physical Activity Guidelines for Americans (i.e., aerobic activity, muscle strengthening and sedentary behavior). Before every potential combination of Core + Candidate weight neutral components can be tested in a fully powered factorial experiment, we will conduct necessary pilot testing in this Preparation phase study to ensure we can recruit our target sample and deliver the novel combinations of weight neutral components as intended. To make strategic use of resources, a fractional factorial design will be deployed. The Core intervention and conditions with 2+ weight neutral candidate components will be pilot tested. Small groups of racially/ethnically diverse adults with BMI 25-40kg/m2 (n=50) will be recruited and randomly assigned to one of the five treatment combinations. This project will leverage the expertise the PI has developed through completion of her NIDDK-funded K23 and enhance her capacity to transition to independence by launching a related but distinct line of research investigating the health benefits of weight neutral lifestyle interventions for individuals of higher body weight.