Estimation of food portion sizes frequently consumed by children 3-6 years old in Japan.

No study has documented Japanese children's food portion sizes. Since this information is essential to establish valid measurement tools and effective education methods for dietary intake, we measured them using one-day, semi-weighed diet records (DRs) for 489 Japanese children aged 3-6 y. Each food's frequency of appearance on the DRs was counted. If a child consumed a certain food more than once per day, an average weight for that food was calculated and used in the portion size calculation as that child's representative value. In total, 67 food items were consumed by twenty or more children. We calculated the mean, standard deviation, median, minimum, and maximum portion size values for these food items. In addition to these 67 items, Chinese noodles and water were included in the analysis. The most frequently consumed food was well-milled rice (mean portion size for rice=79 g), which was consumed by 350 children, followed by soy sauce (4 g), eggs (26 g), and carrots (9 g). Among the five most frequently consumed foods, portion sizes of rice and pork but not milk, eggs, or carrots significantly increased with age, height, and weight. In multivariate linear regression analysis, however, the significant relationships between rice portion size and age were not observed. Regarding pork, only the relationship with height was significant. A sex difference was detected in the rice and milk portion sizes. Most of portion sizes observed here were apparently smaller than those reported among United Kingdom children. This study provides important basic information for the implementation of quantitative nutritional research and educational efforts for Japanese preschool children.