Fig. 1.

Outline of the study. A Recruitment of primary schools. Seven cities and towns were chosen from each of five administrative districts in the prefecture. Two public primary schools with similar characteristics were then selected from each city/town. For the two schools from each city/town, one was assigned to the First group and the second to the Second group, such that the First and Second groups included seven schools each. B Schedule. Questionnaire surveys were performed three times (May, October, and February). The nutrition education program (intervention) was given between the surveys. The intervention was implemented between June and September for the First group and between October and January for the Second group in an alternating manner