Dyad and group-based interventions in physical activity, diet, and weight loss: a systematic review of the evidence.

Studies show that interpersonal relations impact behavior change. Yet, a comprehensive review of their efficacy remains unclear. This systematic review examines the efficacy of dyadic and group-based studies that intervened on primary endpoints: diet, PA, and weight loss in adults and their networks. We searched five databases for eligible articles published from 1980 to present. Final inclusion and risk of bias were independently determined and agreed upon by two of the paper's co-authors. Nine dyads and twelve group-based studies were eligible. Of the studies, 36% (4/11) of PA studies, 60% (3/5) of diet studies and 57% (8/14) of studies with weight loss as primary outcomes, reported significant findings. Compared to dyadic interventions, a greater proportion of group-based interventions demonstrated efficacy in PA gain and weight loss as outcomes. Approximately 43% of studies demonstrated low to moderate methodological quality. This systematic review synthesized the evidence of dyadic and group studies that intervened on PA, diet, and weight in adults from the same network. Moderately-high risk of bias and lack of diverse representation restricts inferences around efficacy. High-quality rigorous research is needed to understand the efficacy of dyadic and group-based interventions in addressing these co-occurring endpoints of interest.