Lifestyle behaviors associated with the population-level double burden of malnutrition among middle school students in Saudi Arabia: a cross-sectional study

Background The coexistence of undernutrition and overweight/obesity, commonly referred to as the double burden of malnutrition, is an important public health concern among adolescents. This study assessed the population-level double burden of malnutrition among middle school students and examined its associations with selected lifestyle behaviors. Methods A cross-sectional study was conducted among 268 middle school students recruited from four schools selected using stratified cluster sampling. Analyses incorporated sampling weights and the complex survey design. Data on dietary habits, physical activity, and screen-related behaviors were collected using a structured self-administered questionnaire. The research team obtained anthropometric measurements, including height and weight. Nutritional status was classified using the World Health Organization BMI-for-age reference. Statistical analyses incorporated sampling weights and the complex survey design, with associations examined using the Rao–Scott design-adjusted chi-square test. Results Survey-weighted estimates showed that 49.8% of the represented population had an abnormal BMI-for-age classification: 25.3% were underweight and 24.5% were overweight or obese, indicating a population-level double burden of malnutrition. In the design-adjusted bivariate analyses, eating while using screens was the only behavior significantly associated with BMI category ( p = 0.046). The weighted prevalence of overweight/obesity increased from 12.1% among students who never ate while using screens to 32.9% among those who always did so. Demographic characteristics, dietary behaviors, physical-activity frequency, screen-time duration, mobile-phone use, and eating while using a mobile phone were not statistically significant. Conclusion Underweight and overweight/obesity coexisted at similar levels in the represented middle-school population. Eating while using screens was associated with BMI category in the design-adjusted bivariate analysis; however, the cross-sectional design and limited number of sampled schools require cautious interpretation. The findings support school-health strategies addressing both forms of malnutrition and promoting balanced dietary practices, regular physical activity, and reduced screen-related eating.