Obesity is a public health problem influenced by behavioral patterns that span an ecological spectrum of individual-level factors, social network factors and environmental factors. Both individual and environmental approaches necessarily include significant influences from social networks, but how and under what conditions social networks influence behavior change is often not clearly mapped out either in the obesity literature or in many intervention designs. In this paper, we provide an analysis of recent empirical work in obesity research that explicates social network (...) influences on eating behaviors. We argue that a relational rather than individualistic view of personhood should help us better understand the content and context of social network relations that inform health behavior choices. We introduce the concept of ‘identity-constitutive affiliations’ as the glue that binds these social relationships together. Finally, we outline the implications for public health ethics in the development of effective interventions to address overweight and obesity, leveraging the content and context of social network ties to reinforce healthy (or alter unhealthy) eating. More complex treatment of positive and negative behaviors stemming from social network connections should lead to more comprehensive theoretical models of health behavior change and more effective public health interventions. (shrink)