The objective of this study was to evaluate the social network, food patterns, physical activity, and their associations with overweight/obesity in adolescents from a school in rural Brazil. Students from a rural school in Northeast Brazil (n = 90) completed questionnaires on sociodemographic characteristics, food consumption, physical activity, and a name generator. Social networks were constructed using students’ social proximity ties. Principal component analysis was performed to determine food patterns, and logistic models were used to investigate variables associated with overweight/obesity. Most participants were girls (62.9%), and the proportion of overweight/obesity was 30% among adolescents. Students cited 2070 people from their networks (family, friends at school, friends outside of school, and others). Among them, the family had the highest degree of influence (61%) in the network and had the most shared meals with adolescents (47%). Adolescents’ perception of their family members’ body size as obese, compared to normal or underweight, was prevalent (51%). Adolescents with unhealthy food patterns were 72% more likely to be categorized as overweight/obese, and eigenvector centrality was also associated with overweight/obesity (OR = 5.88, 95% CI = 1.08–32.03). Adolescents presented a social network with strong family influence, in which a high percentage of overweight/obesity was observed. Adolescents with high eigenvector centrality were more likely to be in the overweight/obesity category. Additionally, overweight/obesity was associated with unhealthy food patterns in the family network.

This narrative review examines the influence of social networks on dietary habits and physical activity, and their relationship to overweight and obesity in adolescents. The study is based on a comprehensive literature search across PubMed, Scopus, EMBASE, PsycINFO, and Web of Science databases, covering the period 2009–2022, and is complemented by a critical analysis of contemporary evidence. The included studies involved adolescents aged 12 to 19 and assessed associations among social networks, body weight, diet, and physical activity, using statistical methods based on social network analysis (SNA). No language restrictions were applied. The results demonstrated that friendship networks significantly influence adolescents’ body weight, eating behaviors, and physical activity levels. Specifically, boys exhibited similar unhealthy food consumption patterns within their networks, while girls’ networks showed similarities in sedentary activities. This review highlights that adolescents’ social networks play a relevant role in weight-related behaviors, with their influence varying based by gender. These findings underscore the need to consider such gender-specific effects when developing prevention and treatment strategies for obesity in this age group.