Association between dietary knowledge and overweight/obesity in Chinese children and adolescents aged 8–18 years: a cross-sectional study

BACKGROUND: A lack of adequate dietary knowledge may result in poor health. The purpose of this study was to study the association between dietary knowledge and overweight/obesity in children and adolescents. METHOD: Data from the China Health and Nutrition Survey (CHNS) 2004, 2006, 2009, 2011, and 2015 were used in this cross-sectional study. The dietary knowledge of children and adolescents was evaluated by the questionnaire in the database. The overweight and obesity status was evaluated by body mass index (BMI). Cluster analysis was performed to establish different groups based on dietary knowledge level. Logistic regression analysis and subgroup analysis were conducted. RESULTS: A total of 2,701 children and adolescents were finally selected. Cluster A (n = 837, 30.99%), Cluster B (n = 1,264, 46.80%) and Cluster C (n = 600, 22.21%) were high, medium and low dietary knowledge level, respectively. Participants with high dietary knowledge levels [OR = 0.56 (95%CI: 1.40–0.78)] may be negatively associated with overweight and obesity. Similar results were found among adolescents, males, females, people living in eastern and northeastern China, and rural areas, after adjusting for age, gender, geographic region, maternal education level, alcohol consumption, waist-to-hip ratio, systolic blood pressure and diastolic blood pressure. CONCLUSION: Improving the dietary knowledge level of children and adolescents was associated with decreased risk of overweight and obesity. Our study provided a theoretical basis for the relationship between dietary knowledge and overweight/obesity in Chinese children and adolescents and suggested strengthening the publicity and popularization of dietary knowledge in schools and communities. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12887-022-03618-2.