Childhood obesity has increased in recent decades in Korea. This study was designed to examine differences in the eating habits, physical activity (PA), nutrition knowledge, and self-efficacy of children by obesity status.

Subjects were 5th-grade children from 70 elementary schools in 17 cities nationwide. Two-stage stratified cluster sampling was employed. Survey questionnaire included items related to general characteristics, eating habits, PA, nutrition knowledge and self-efficacy. Excluding incomplete responses, 3,531 data were analyzed using SPSS. Subjects were categorized into overweight·obesity (OW) and normal weight (NW) groups based on body mass index percentiles for age by sex.

A total of 21.5% of subjects was overweight or obese. There were significant differences in gender, perceived stress, perception of body shape, body satisfaction, and interest in weight control between the OW and NW groups ( P < 0.001). With respect to eating habits, the OW group ate breakfast ( P < 0.05) and snacks ( P < 0.01) less frequently, ate bigger meals ( P < 0.001), and demonstrated less desirable behaviors during meals ( P <0.05 in boys) compared to the NW group. The OW group participated in less PA than the NW group, especially boys. OW boys spent less time walking during weekdays ( P < 0.05) or the weekend ( P < 0.001), spent more time being sedentary during weekdays or the weekend ( P < 0.001), and exercised a fewer number of days ( P < 0.01). For girls, the OW group spent more time being sedentary during the weekend ( P < 0.01) and exercised a fewer number of days by walking or bicycle riding ( P < 0.05) than the NW group. Nutrition knowledge was not significantly different between the OW and NW groups. Self-efficacy ( P < 0.01 in boys), especially PA self-efficacy ( P < 0.01), was significantly lower in the OW than NW group.

This study revealed differences in eating habits, PA, and self-efficacy between OW and NW children. Obesity management programs for children need to focus on increasing self-efficacy, modifying eating habits, and increasing PA.