1 Research Center of Sainte Justine University Hospital, Université de Montréal, Montréal, Québec, Canada.
2 Department of Family Medicine, McGill University, Montréal, Québec, Canada.
3 Epidemiology and Biostatistics Unit, Center Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique, Université du Québec, Laval, Québec, Canada.
4 Ingram School of Nursing, McGill University, Montreal, Québec, Canada.
5 Department of Pediatrics, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada.
6 Department of Mathematics and Statistics, Concordia University, Montreal, Québec, Canada.
7 Institut Santé et Société, Université du Québec à Montréal, Montréal, Québec, Canada.
8 Department of Social and Preventive Medicine, School of Public Health, Université de Montréal, Montréal, Québec, Canada.

Background and Objective: Weight-related behaviors are determined by multiple individual and contextual factors, with recent evidence implicating personal social networks (PSNs). Greater understanding of these relationships could help inform healthy weight promoting interventions. We conducted a feasibility study among youth at risk of obesity to document process outcomes, to discern relationships between PSN features and weight-related behaviors, and to generate hypotheses with respect to perceived social support (SS) and sex. Methods: Participants (egos) nominated up to 10 people (alters) with whom they discussed important matters. Egos reported their own and each alter's age, sex, body shape, lifestyle behaviors, relation, frequency of exercising with each alter, and of being encouraged by each alter to exercise. We examined relationships between PSN features and weight-related outcomes and explored the role of SS, using both correlational and linear regression analyses. Results: There were 45 participants (mean age 16.4 years) and body mass index z-score (zBMI) ranged from -1.2 to 3.9. There were few missing responses to PSN items; broad variation across most items, including SS scores, was reported. Correlations pointed to plausible relationships implicating PSN features and lifestyle behaviors. In exploratory analyses, network-based SS was positively associated with adiposity in girls and negatively associated in boys, while lifestyle role modelling was not associated with adiposity. Conclusions: Our findings support the feasibility of measuring the PSN in youth and the potential for using social network analysis to investigate social and behavioral mechanisms associated with obesity.