Background: Over 40% of Veterans have obesity, a risk factor for multiple chronic diseases. Weight loss interventions produce clinically significant weight loss, yet weight regain commonly occurs due to declining adherence to lifestyle changes. These changes are often substantially influenced by others in the home. Thus, involving both Veterans and a cohabiting support person in weight management efforts could improve long- term weight loss. The goal of the proposed trial is to evaluate the efficacy of involving romantic and non- romantic support persons in weight management efforts to sustain long-term weight loss in Veterans. Significance: This study will contribute to our long-term goal of implementing effective approaches to reduce obesity and associated comorbidities among Veterans. This proposal addresses Health Services Research & Development priorities of access, primary care practice, and virtual care and Office of Research & Development priority of providing Veterans with access to high-quality clinical trials. The importance of identifying efficacious strategies for weight loss maintenance was highlighted in a 2016 State-of-the-Art conference on weight management. Innovation: We will substantially enhance prior work and the MOVE! program offered through the VA by 1) teaching Veterans and their support persons to apply communication and support skills to support Veteran weight management and 2) focusing on long-term weight loss. Specific Aims: Aim 1: Compare effects of patient-only and partner-assisted interventions on long-term weight loss (primary outcome) and obesity-specific quality of life (secondary outcome). Our primary hypothesis is that average weight loss from baseline among Veterans will be at least 3 percentage points greater, a clinically meaningful difference, in the partner-assisted arm than the patient-only arm at 72 weeks. Aim 2: Evaluate the extent to which early intervention effects are mediated by changes in interdependence theory constructs (transformation of motivation, couple efficacy, outcome expectancy, and social support). Aim 3: Evaluate implementation outcomes of appropriateness, acceptability, and feasibility among MOVE! Coordinators via validated surveys and qualitative interviews, and evaluate treatment receipt and enactment among a subset of participating Veterans and support persons via qualitative interviews. Methodology: This is a two-arm randomized trial. Participants: Dyads comprising a Veteran with obesity and a cohabiting adult support person. Intervention: Index patients will participate in a group-based weight management program using the Veterans Affairs (VA) national MOVE! weight management curriculum and delivered using the VA virtual technology platform, VA Video Connect. Support persons will join the sessions, and dyads will learn and practice communication skills. Comparison: Veterans will participate in the weight management program without a support person. Outcomes: The primary outcome is percent weight loss from baseline. Time: The intervention is 72 weeks in duration. Outcomes will be assessed at baseline and every 24 weeks, with 72 weeks as the primary endpoint. Implementation: We will assess MOVE! coordinator perceptions of intervention appropriateness, acceptability, and feasibility and Veteran treatment receipt and enactment in Aim 3. Armed with this information, we will be poised to study implementation in the future. The materials developed in this study could be disseminated and implemented as an optional module by MOVE! Coordinators.

Over 40% of Veterans have obesity, a condition associated with multiple comorbidities and high healthcare costs. While lifestyle interventions addressing dietary change and physical activity produce clinically significant weight loss, many individuals experience weight regain due to decreased adherence to these changes. In this two-arm, randomized trial, Veterans with obesity and a cohabitating adult support person will be randomized to participate in a virtual weight loss intervention based on the VA’s MOVE! program with or without their support person. Those who participate with their partner will learn and practice communication and support skills. We predict that the dyadic intervention will result in greater weight loss, improved social support, and enhanced quality of life at 72 weeks compared to the patient-focused intervention. If effective, the support intervention will contribute to the identification and implementation of successful, evidence-based approaches to reduce the prevalence of obesity and associated comorbidities among Veterans.