Influence of body image in urbanized areas: Differences in long-term changes in teenage body mass index between boys and girls in Japan

Japanese prefecture level panel data for the period 1986–2003 was used to analyze and compare the determinants of teenage body mass index (BMI) by sex. Major findings through random effects estimation were as follows: (1) BMI consistently increased during the period in males aged 10–16 and in females aged 10–13 years, but not in 16-year-old females; (2) BMI was not influenced by the degree of population density in males and younger females. However, the BMI of 16-year-old females was markedly lower in more densely populated residential areas. These findings suggest that girls who reach adolescence are more likely to diet and that this tendency is more distinct in more urbanized areas.