Electronic Thesis and Dissertation Repository

Thesis Format



Master of Science


Epidemiology and Biostatistics


Sarma, Sisira


Improving diet quality is an important public policy initiative targeted to enhance population health worldwide. In this regard, school nutrition policy is an important means to promote healthy diet among children and youth. In Canada, six provinces implemented mandatory school nutrition policies at different times between 2005 and 2011. We investigated the impact of mandatory school nutrition policy on diet quality of Canadian children and youth using a quasi- experimental study design. Using 24-hour dietary recall data from the 2004 Canadian Community Health Survey (CCHS) Cycle 2.2 and 2015 CCHS-Nutrition, we constructed the Diet Quality Index (DQI). We used multivariable difference-in-differences regression models to quantify the effect of school nutrition policy on diet quality. We conducted stratified analyses by sex, school grade, and household income to gain additional insights into the effect of nutrition policy. We found that the effect of mandatory school nutrition policy on diet quality, measured by DQI, increased by 4.34 points (95% CI: 1.83 - 6.85) per child during school-hours in provinces with mandatory nutrition policy compared to control provinces. Although the confidence intervals overlap, the effect was higher among males (6.51 points, 95% CI: 2.93 - 10.09) compared to females (2.14 points, 95% CI: -1.25 - 5.52), and the effect among children in elementary schools was higher (4.82 points, 95% CI: 1.97 - 7.67) compared to those in high schools (3.37 points, 95% CI: -1.22 - 7.95). Our findings suggest that other jurisdictions may consider implementing mandatory school nutrition policy.

Summary for Lay Audience

Numerous studies show that children and youth are not meeting the recommendations of Canada’s Food Guide. Studies of food consumption among Canadian children report that more than half ate less than the minimum recommended daily servings of fruits and vegetables, milk products, and grain products. Because poor diet is associated with the incidence of many preventable chronic conditions, nutrition has been identified as a focus point for initiatives aimed at improving the health of children. One such initiative targeted directly at children and youth are school nutrition policies. This thesis evaluated the effect of mandatory school nutrition policies on diet quality of Canadian children and youth using data from the Canadian Community Health Surveys collected by Statistics Canada. Using 24-hour diet recall data, diet quality scores (on a scale of 0 to 100) were calculated. Mandatory provincial school nutrition policy increased diet quality of children during school-hours compared to provinces with voluntary school nutrition policy. Males and elementary school students had greater improvements in diet quality during school hours. The findings suggest that other provinces may consider implementing mandatory school nutrition policies.