Assessing Changes in Adolescents' Sleep Characteristics and Dietary Quality in the START Study, a Natural Experiment on Delayed School Start Time Policies

Kelsie M. Full, Aaron T. Berger, Darin Erickson, Kaitlyn M. Berry, Melissa N. Laska, Kathleen M. Lenk, Conrad Iber, Susan Redline, Rachel Widome

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


BACKGROUND: Sleep duration, quality, and timing may influence dietary quality. In adults, poor dietary quality is a risk factor for numerous chronic diseases. It is unclear how these various sleep domains influence adolescents' diets because prior population-based studies have not effectively manipulated sleep, did not include objective sleep measures, and had short follow-up times.

OBJECTIVES: The objectives of this study were to examine 1) how adolescent sleep characteristics relate to dietary quality; and 2) how delay in high school start times (which lengthened sleep duration) affects dietary quality over 2 y.

METHODS: In the START study, adolescents (grades 9-11, n = 423) attending 5 high schools in the Minneapolis, Minnesota metropolitan area were annually assessed in 3 waves (2016-2018). At Baseline, all schools started "early" (07:30 or 07:45). From Follow-up 1 through Follow-up 2, 2 "policy change schools" shifted to later start times (to 08:20 and 08:50). Three "comparison schools" maintained their early start throughout. Sleep characteristics were measured with actigraphy. Mixed-effect regression models were used to examine cross-sectional and longitudinal associations of sleep characteristics with dietary quality, and school start time policy change with dietary quality change.

RESULTS: Cross-sectionally, later sleep midpoint and onset were associated with dietary quality scores 1.6-1.7 lower (both P < 0.05). However, no prospective associations were observed between sleep characteristics and dietary quality in longitudinal models. Shifting to later school start time tended to be associated with a 2.4-point increase in dietary quality score (P = 0.09) at Follow-up 1, but was not associated with change in dietary quality scores at Follow-up 2 (P = 0.35).

CONCLUSIONS: High school students attending delayed-start schools maintained better dietary quality than students in comparison schools; however, differences were not statistically significant. Overall study findings highlight the complexity of the relation between sleep behavior and diet in adolescence.

Original languageEnglish (US)
Pages (from-to)2808-2815
Number of pages8
JournalJournal of Nutrition
Issue number9
StatePublished - Sep 1 2021

Bibliographical note

Publisher Copyright:
© 2021 The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition.


  • actigraphy
  • adolescence
  • diet
  • high school
  • school start times
  • sleep timing


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