Associations Between School Start Times and Adolescent Dietary Intake: Results From a National Study

Earlier school start times have been associated with poorer adolescent health outcomes. However, there is limited research on the associations between school start times and diet. The present study aimed to assess associations between school start times and dietary intake in a national sample of US adolescents. Earlier school start time was expected to predict greater energy-dense, nutrient-poor food intake and less healthful/beneficial food intake concurrently. Participants (n = 1371, M_age = 14.51 years, 51% female) were from the National Cancer Institute's Family Life, Activity, Sun, Health, and Eating (FLASHE) study. Weighted least-squares regressions (with raked weights adjusting for the US population demographics) assessed school start time as a predictor of top-coded eating scales, controlling for demographic and socioeconomic factors. Adolescents who attended schools with earlier start times consumed more energy-dense, nutrient-poor foods which was largely accounted for by greater intake of sugar-sweetened beverages and teaspoons of sugar. Surprisingly, earlier start times were also associated with greater fruit intake. Post hoc analyses of separate variables indicated earlier school start time predicted cups of fruit but not vegetables. Future researchers are encouraged to examine school start time associations with dietary consumption using longitudinal designs and greater nuance in dietary assessment.