Psychological stress and processed food consumption as predictors of body mass index in schoolchildren

Abstract Background The increasing prevalence of childhood obesity has been associated with emotional and behavioral factors, such as psychological stress and dietary habits. Thus, this study aimed to investigate the associations between psychological stress, food consumption, and Body Mass Index (BMI) in Brazilian schoolchildren aged 10 to 12 years, considering sex and school type (public vs. private). Methods A cross-sectional study was conducted with 120 children (60 boys and 60 girls) from public and private schools in southeastern Brazil. BMI was calculated based on anthropometric measurements. Food consumption was assessed during an experimental meal, focusing on caloric and gram intake of processed and unprocessed foods. Psychological stress was measured using the validated Children’s Stress Scale. Two-way ANOVA was used to assess differences by sex and school type, and multiple linear regression identified BMI predictors. Results Boys and public school children consumed significantly more processed foods ( p < 0.001), and boys also had higher caloric intake from unprocessed foods ( p = 0.046). Significant interactions between sex and school type were found in the stress domains of Psychological Reactions ( p = 0.006) and Psychological Reactions with Depressive Components ( p = 0.039), with public school boys showing the highest scores. Psychological stress was the only significant predictor of increased BMI ( p < 0.05) in the regression model. Conclusion Higher psychological stress levels were positively associated with increased BMI in school-aged children. These findings underscore the importance of considering emotional and behavioral factors in childhood obesity prevention strategies, particularly in socially vulnerable school contexts.