A cross-sectional study of breakfast skipping and body composition among young adults.

Background: Although breakfast provides essential nutrients and energy, skipping this meal has become increasingly common among young adults in Korea. In this study, we examine the relationship between breakfast consumption and body composition.

Methods: We analyzed data from 17,763 students aged 18-39 at Seoul National University (2018-2022). Participants were categorized based on their breakfast frequency: non-skippers, 1 to 3-day skippers, and 4 to 7-day skippers. Measurements included body mass index, waist circumference, body fat percentage, fat mass index (FMI), fat-free mass index (FFMI), and skeletal muscle mass index (SMI). Multivariable logistic and linear regression models adjusted for age, sex, alcohol use, smoking, physical activity, sleep, and food consumption frequencies were used.

Results: Obesity (17.4% vs. 14.8%) and abdominal obesity (10.0% vs. 7.8%) were higher in those skipping breakfast 4 to 7 d/wk compared with non-skippers. Skipping breakfast was not significantly associated with abdominal obesity in either sex. In women, the odds of obesity were higher (odds ratio, 1.57; 95% confidence interval, 1.14-2.15; P=0.006), whereas no significant difference was observed in men. Men who skipped breakfast had increased body fat percentage (coefficient, 0.87; P<0.001) and FMI (coefficient, 0.18; P=0.009) and decreased FFMI and SMI. Women showed increased body fat percentage (coefficient, 0.92; P<0.001) and FMI but no significant differences in FFMI or SMI.

Conclusion: Skipping breakfast adversely affects body composition by increasing body fat percentage and FMI. Further research is needed to confirm these findings and explore the underlying mechanisms.