How online health groups help you lose weight: The role of group composition and social contact

Online health-specific goal challenge groups gather people with the same health concerns and provide an environment to keep on track, exchange experiences, and compete for achievements. We examine how group health status composition influences social contact, and how both group health status composition and social contact affect individual health achievement. Using longitudinal data from 2479 online health challenge group users and their corresponding group information, we found that (a) compared with individual health status, group conditions (average weight status and member affiliation) are more strongly connected with social contact; (b) different mechanisms affect whether people participate in social contact and increase their participation, and weight loss; and (c) average group condition influences individuals’ weight loss through social contact. We emphasize the effect of group composition and the social contact process in health enhancement.