Motivational interviewing with parents of overweight children: study design and methods for the NOURISH + MI study

There is an urgent need for innovative approaches to pediatric obesity treatment. There is also a demand for targeted strategies that reduce attrition and improve treatment adherence. Intervening exclusively with parents of overweight children is a novel approach with demonstrated efficacy in reducing child body mass index (BMI) percentile. Motivational interviewing (MI), a brief communication style for exploring and resolving ambivalence about behavior change, might enhance treatment engagement when implemented as part of obesity interventions. The aim of this report is to provide the rationale and methods for a novel study of MI with parents in the treatment of their children's overweight. We designed and are currently implementing NOURISH+MI, a randomized controlled trial examining the feasibility and efficacy of an adjunct values-based MI intervention, implemented within a culturally-tailored parent intervention for overweight children ages 5-11 years, NOURISH(+) (Nourishing Our Understanding of Role modeling to Improve Support and Health). Specifically, we are randomly assigning 60 parents to this adjunctive treatment, and investigating if adding two MI sessions prior to the NOURISH(+) group intervention will enhance treatment effects. We will be able to compare NOURISH+MI participants with those from the two NOURISH(+) treatment conditions (NOURISH(+) and control). We hypothesize that children whose parents participate in NOURISH+MI will demonstrate lower attrition and greater adherence with NOURISH(+), ultimately leading to greater treatment effects, compared with children whose parents are randomized to NOURISH(+) or a control group. Findings will contribute to the emerging literature examining the efficacy of MI within pediatric obesity interventions.