Association of Body Mass Index with Moderate-Intensity Physical Activity, Eating Behavior, and the Use of the Internet or Games among Korean Middle School Students.

Background/objectives: This study aimed to investigate the association of body mass index (BMI) with the weekly frequency of moderate-intensity physical activity, eating behavior, and the use of the Internet or games among Korean middle school students.

Methods: The data of 23,583 Korean middle school students were collected from the 2023 Korean Student Health Examination. The collected data were analyzed using frequency, chi-square, and multivariate logistic regression analyses.

Results: The results also showed that the higher the BMI, the greater the likelihood of moderate-intensity physical activity. The likelihood of breakfast intake reduced as the BMI increased. However, the likelihood of using the Internet or games increased with an increase in BMI. The results revealed that 28% (6594 of 23,583) of middle school students rarely participate in moderate-intensity physical activity, while 32% (7553 of 23,583) participate only once or twice a week. The results also showed that the higher the BMI, the higher the likelihood of moderate-intensity physical activity. Among those who were underweight, the odds ratio (OR) of 3-4 days of participation in moderate-intensity physical activity was 0.764 (95% confidence interval [CI]: 0.664-0.880; < 0.001). Among those who were healthy, the OR of more than 5 days of participation was 1.279 (95% CI: 1.131-1.446; < 0.001). Among those who were overweight, the OR of 3-4 days and more than 5 days of participation was 1.172 (95% CI: 1.019-1.348; = 0.026) and 1.181 (95% CI: 1.011-1.380; = 0.036), respectively. The likelihood of the use of the Internet or games increased with an increase in BMI. The OR of the use of the Internet or games was 0.876 (95% CI: 0.806-0.952; = 0.002) and 0.824 (95% CI: 0.743-0.913; < 0.001) among those who were healthy and those who were overweight, respectively. However, the likelihood of breakfast intake reduced as the BMI increased. Among those who were underweight, the OR of always eating breakfast and mostly eating breakfast was 1.299 (95% CI: 1.114-1.515; < 0.001) and 1.236 (95% CI: 1.045-1.461; = 0.013), respectively. Among those who were healthy, the OR of always eating breakfast was 1.157 (95% CI: 1.026-1.305; = 0.018). Among those who were overweight, the OR of mostly eating breakfast was 1.215 (95% CI: 1.030-1.433; = 0.021).

Conclusions: Given this, outdoor sports may increase adolescents' participation in physical activities by helping them break away from repetitive ball games and increasing their overall interest and participation in physical activities. Overall, our results suggest the need to move away from traditional physical education and develop engaging physical activity programs that motivate students to participate in moderate-intensity physical activities.