[영문]OBJECTIVES: We investigated temporal patterns from 1984 to 2006 in 6 weight-related health behaviors by using longitudinal data for multiple cohorts of young adults (aged 19?26 years) from the nationally representative Monitoring the Future Study. METHODS: We used growth curve models to examine historical trends in 6 health behaviors: frequency of eating breakfast, eating green vegetables, eating fruit, exercising, watching television, and sleeping 7 hours each night. Variations across gender, race/ethnicity, and socioeconomic status were investigated. RESULTS: Frequency of exercising was consistently lower among young adult women than young adult men over this 23-year period. Compared with White women, Hispanic women, and women from other race/ethnic groups, Black women showed declines in the frequency of exercise since 1984. In general, young adult women showed a marked increase in the frequency of eating breakfast over this period, although Black women did not show any net gains. CONCLUSIONS: Social disparities in body weight may increase because Black women, Hispanic women, and men with lower socioeconomic status show declining trends in positive weight-related health behaviors compared with White young adults with higher socioeconomic status.