Purpose
Emerging evidence indicates that eating patterns—particularly skipping meals and eating alone—are associated with excess body weight. However, few studies have assessed whether these behaviors contribute to weight gain across different age groups. This study examined the associations of skipping breakfast or dinner, and of eating those meals alone, with overweight or obesity among Korean adults compared to children and adolescents. Methods: This cross-sectional secondary analysis used data from the 2019 Korea National Health and Nutrition Examination Survey. Information on skipping meals, eating alone, and sociodemographic characteristics was obtained via self-report for adults and proxy report for participants under 12 years of age. Overweight or obesity was determined from measured height and weight. Multivariable logistic regression analyses were performed separately by age group. Results: Among adults, eating dinner alone was associated with higher odds of obesity (odds ratio [OR]=1.27, 95% confidence interval [CI]=1.06–1.52). Among adolescents, skipping dinner three or more times per week was associated with higher odds of obesity (OR=2.60, 95% CI=1.04–6.54). No significant associations were observed in children. Skipping breakfast or eating breakfast alone was not significantly associated with overweight or obesity in any age group. Conclusion: Although the cross-sectional design precludes causal inference, the findings suggest age-specific links between eating behaviors and weight status. For adults, reducing solitary dinners may help prevent obesity, whereas for adolescents, preventing frequent dinner skipping could be beneficial. Nursing strategies promoting shared mealtimes in adults and regular dinners in adolescents may help address obesity in Korea.