Objective  To explore the relationship between dietary behavior and nutritional status and its gender difference among school-age children.

  Methods  Using stratified cluster sampling, we recruited 1 137 grade 3 – 6 pupils (mean age = 9.89 ± 1.32 years) in two primary schools in urban and rural Hefei city of Anhui province for a cross-sectional survey in November 2018. For all the pupils, measurements of height, weight, subscapular and upper arm skin-fold thickness were conducted for determinations of body mass index (BMI) and percentage of body fat; peripheral blood hemoglobin, trace elements as calcium, iron, zinc were also detected. The Children's Eating Behaviour Questionnaire was answered by the pupils' major caregivers. Multivariate logistic regression was used to analyze associations of dietary behavior with nutritional indicators among the pupils.

  Results  The prevalence of overweight and obesity was 23.39% (244/1 043) in the school-age children. The detection rates were 22.15% (n = 231), 18.22% (190), 11.89% (124), and 8.82% (92) for deficiency of calcium, iron, zinc, and hemoglobin, respectively. There were significant urban-rural differences in all dimension scores of dietary behavior for the children, except for the score for emotional undereating (all P < 0.05). After adjusting for demographic variables, multivariate logistic regression analysis showed that satiety response reduced the incidence of high-fat and overweight obesity; while, food response was a risk factor for both high-fat and overweight obesity, but a protective factor against anemia (all P < 0.05). After gender stratification, the effect of satiety response on low body fat was significant only in the boys; while the effect on high body fat and overweight and obesity were significant in both the boys and the girls; the effect of food response on anemia was significant in the boys and the effect on high fat and overweight and obesity was significant in the girls; the effect of eating slowly on high body fat and overweight and obesity was significant only in the boys (all P < 0.05).

  Conclusion   Dietary behaviors are of a great impact on obesity and body fat in school-age children, suggesting that caregivers should actively cultivate the children's good dietary habits to promote their health.