Normalization of overweight and obesity in family relations: a personal network analysis study

Background Most research on weight status perception focuses on self-evaluation, with studies on perceptions of others largely limited to parent–child assessments. Moreover, studies incorporating a network analysis design into how social relations influence weight perception are even fewer and focused rather on friendship networks from school data. The aim of this study is to investigate the accuracy of evaluations made by respondents regarding the BMI category of persons from their social circle. Methods We analysed 444 evaluator–evaluated dyads from a Personal Network Analysis study including respondents (egos) and their close contacts (alters). Egos self-reported height and weight were used to compute BMI (kg/m²) and BMI categories. Alters’ weight status was assessed by egos using BMI-based pictograms. Only pairs where both egos and alters were respondents were retained, enabling comparison between actual BMI category and perceived category. Cross-classified logistic regression models examined accuracy, underestimation, and overestimation as binary outcomes in separate regression models. Results When alter BMI category and family member status interacted, respondents were more likely to underestimate (OR 4.74, 95% CI 1.74–12.92, p  = 0.002) family members or be accurate (OR 0.37, 95% CI 0.18–0.74, p  = 0.005) in evaluating non-family members, with no significant effect for overestimation (OR 1.18, 95% CI 0.50–2.78, p  = 0.713). Underestimation was also associated with broader network perceptions: respondents reporting few alters matched to overweight-or-higher body figures were more likely to underestimate others’ BMI category (OR 0.29, 95% CI 0.19–0.45, p  < 0.001). Conclusions Findings suggest weight control programs and health interventions, in general, should address not only self-perception but also network influences. Underestimation biases within family relationships may persist into adulthood, potentially limiting social support for weight management and other health-related behaviours.