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Sugar rush or sugar crash? Experimental evidence on the impact of sugary drinks in the classroom

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Sugary drinks in schools have been demonized for their potential long‐term contribution to rising obesity rates. Surprisingly, there is only little evidence on the immediate effects of sugary drinks in schools. This paper provides experimental evidence on the in‐class effects of sugary drinks on behavior and student achievement. We randomly assigned 462 preschool children to receive sugary drinks or artificially sweetened drinks and collected data before and after consumption. Our findings suggest that the consumption of one sugary drink induces an initial “relaxing” effect for boys, before making them more restless. Girls' behavior is not significantly affected. We find a negative effect on student achievement for boys and a positive effect for girls. We show the robustness of the results across two field experiments.
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 | INTRODUCTION
Parents and educators care a lot about the diet of their children. At the same time, the percentage of children in the Unit-
ed States consuming sugary drinks1 rose from 79% to 91% between 1989 and 2008 (Lasater etal.,2011). Data from the
National Health and Nutrition Examination Survey (2007–2010) indicated that 62% of preschool children in the United
States (aged 2–5years) consumed sugary drinks on a daily basis. This share increases with age, corresponding to 73% of
children aged 6–11years and 76% of adolescents aged 12–19years (Bleich & Wolfson,2015). These consumption patterns
can also be seen in Europe, albeit to a much lesser extent. Data from the WHO's European Health Information Gateway
(2014) indicates that 15% of children aged 11years consume soft drinks at least once a day. This share increases to 20% on
average for children aged 15years. In Belgium, where the data collection took place, more than one in four children aged
11years, and more than one in three aged 15years, is consuming soft drinks at least once a day.
Concerns are growing that this “Western diet” high in salt, fat, and sugar—an increasingly global diet—immediately
affects children's physical and mental health (e.g., Gómez-Pinilla,2008). It is a widely held belief that the consumption
of sugary drinks causes children to experience a “sugar rush.2 The associated potential effects on in-class performance
have major policy implications. First, sugary drinks are still ubiquitously sold in schools (Papoutsi etal.,2013). For exam-
ple, the School Nutrition Dietary Assessment of the United States Department of Agriculture reported that one in eight
elementary schools had beverage vending machines in 2010, and more than three quarters offered “competitive foods”
through a la carte offerings. Moreover, in US middle schools (67%) and high schools (85%), vending machines are omni-
present (Fox & Condon,2012). School principals are often the staunchest opponents to the removal of vending machines
1Faculty of Economics and Business, KU
Leuven, Leuven, Belgium
2UNU-Merit, Maastricht University,
Maastricht, the Netherlands
Correspondence
Fritz Schiltz, Faculty of Economics and
Business, KU Leuven, Naamsestraat 69,
3000 Leuven, Belgium.
Email: fritz.schiltz@kuleuven.be
Funding information
European Union's Horizon 2020 research
and innovation programme, Grant/Award
Number: 691676
Abstract
Sugary drinks in schools have been demonized for their potential long-term
contribution to rising obesity rates. Surprisingly, there is only little evidence on
the immediate effects of sugary drinks in schools. This paper provides experi-
mental evidence on the in-class effects of sugary drinks on behavior and student
achievement. We randomly assigned 462 preschool children to receive sugary
drinks or artificially sweetened drinks and collected data before and after con-
sumption. Our findings suggest that the consumption of one sugary drink in-
duces an initial “relaxing” effect for boys, before making them more restless.
Girls' behavior is not significantly affected. We find a negative effect on student
achievement for boys and a positive effect for girls. We show the robustness of
the results across two field experiments.
KEYWORDS
experimental evidence, health economics, student achievement, student behavior, sugary
drinks
RESEARCH ARTICLE
Sugar rush or sugar crash? Experimental evidence on the
impact of sugary drinks in the classroom
Fritz Schiltz1 | Kristof De Witte1,2
DOI: 10.1002/hec.4444
Received: 8 September 2020 Revised: 23 August 2021 Accepted: 27 September 2021
© 2021 John Wiley & Sons, Ltd.wileyonlinelibrary.com/journal/hecHealth Economics. 2022;31:215–232. 215
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