The Short- and Long-term Effectiveness of the WhyDairy? School-based Nutrition Education Intervention: A Randomized Controlled Trial

Megan Racey1, Andrew McKenney1, David Wosnick1, Emma Sypes2, William Albabish1, Genevieve Newton1, *
1 Department of Human Health & Nutritional Sciences, University of Guelph, Guelph ON, Canada, N1G 3W1
2 Department of Biomedical Sciences, University of Guelph, Guelph ON, Canada, N1G 3W1

© 2019 Racey et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Department of Human Health & Nutritional Science, University of Guelph, Guelph, ON, Canada, N1G 2W1; Tel: 519-824-4120; Fax: 519-763-5902; Email:



Despite the known health benefits of dairy products, their daily consumption continues to decline in many populations, particularly in pre-adolescents and adolescents.


The primary objective of the cluster randomized controlled trial was to assess whether a school-based intervention enhanced with a web-based component, known as WhyDairy? was more effective than a standardized dairy education program at changing: (i) knowledge of dairy products, (ii) intentions to consume dairy products, and (iii) dietary intake of dairy products.


Grade 7 students (n=175) in 10 Southwestern Ontario schools were randomized by the school, into intervention or control. Intervention schools received the WhyDairy? intervention with a website component while control schools received a DFO education program. Intervention schools were further randomized to receive follow-up contact, through monthly emails, or no follow-up contact. A questionnaire, consisting of three surveys (knowledge, FFQ, and intention), was delivered at baseline, post-intervention, and follow-up.


All groups significantly increased their knowledge post-intervention but only intervention schools with follow-up email contact maintained this positive change in knowledge. No groups saw significant changes in dietary behaviour. The email campaign was successful in reaching parents but did not result in high engagement or changes in student outcomes.


The results of this study demonstrate the effectiveness of a school-based intervention enhanced with a web-based component in changing student knowledge regarding dairy products and the engagement of the website during the intervention period. Future work should consider longer durations to see changes in dietary behaviour and more targeted approaches during follow-up periods.

Keywords : Adolescents, Dairy products, Intervention, T2D, Obesity, Osteoporosis.