Associations between lunch-time food and school diet quality of Canadian children

Introduction

Schools can provide access to healthy foods via school-food programs and improve children’s eating habits through education. The beneficial effects of school-food programs have been well documented in the USA and Europe. Canada, meanwhile, does not have a national school lunch program or federal standards regarding the quality of foods sold or provided to students in schools. No national study has examined where Canadian children get food during school hours, whether lunch-time food sources are associated with different dietary quality, or whether school hour choices influence whole day diet quality. The objective of this study was to identify potential associations between lunch-time food source, school hour dietary intakes, and school day dietary intakes in Canada. Researchers hypothesized that students who ate off campus lunch-time foods had poorer diets than students who get food from school or bring lunches from home. 

Research Process

Information from the 2004 Canadian Community Health Survey Cycle 2.2 provided nationally representative dietary data in terms of age, sex, geography, and socio-economic status. This survey targeted Canadians living in households across all ten Canadian provinces. Using the 24-hour dietary recall method, researchers asked people about food and beverages consumed the previous day including types of food eaten, serving sizes, eating occasion (ie. breakfast, lunch, dinner), time of consumption, and where the food was prepared. Analysis included participants aged 6-17 years old who reported attending school full time. Food consumed between 9 a.m. and 2 p.m. on school days was considered to be eaten within school hours. Dietary intake variables included amount of energy, macronutrients (e.g. protein), micronutrients (e.g. vitamin C), food group servings, and calories from other more unhealthy foods (e.g. chocolates, candies, etc.). Because dietary quality is a multidimensional concept (i.e. it is not just one food group but refers to multiple dietary components and the balance or proportions between different foods), the authors used the Canadian Healthy Eating Index (C-HEI) to evaluate the quality of foods consumed for the whole day (C-HEI) and during school hours (School-HEI). Scores can range from 0-100 points, where more than 80 points is considered a “high quality diet”, 50-80 points is a diet that “requires improvement”, and a “poor quality diet” is any score below 50 points. The authors examined the associations between lunch-time food source and children’s socio-demographic characteristics. The strengths of this study include the use of a nationally representative sample, and an adapted diet quality indicator (the Canadian Healthy Eating Index) to better interpret the complexity of school diet quality. Limitations included the potential for inaccurate self-reporting, and the possibility that meals may have had portions from multiple sources with only the primary source reported. For example, perhaps a sandwich was homemade and the cookie was store-bought, but the primary source of lunch was reported as homemade. 

Results

Findings showed that 73% of children brought lunch from home, 12% had off-campus lunch, 10% had lunch from school, and 6% missed/reported no lunch. Age and sex were associated with lunch-time food source, with older children obtaining lunch off-campus more often than younger children and boys being more likely to skip lunch. No significant associations were found between any other demographic or socio-economic variables. Home-packed lunches were shown to be significantly higher in total carbohydrates, fibre, vitamins A, D, C, thiamin, and grains compared to lunches from school or off-campus. Home-packed lunches were also shown to be lower in total calories, fat, and calories from unhealthy foods. Home-packed and school lunches had similar levels of vegetables, fruit, and milk products. This suggests home-packed lunches were slightly more nutritious than lunches from off-campus locations, and to a smaller extent, from schools. Students who ate a home-packed lunch had also better whole day dietary quality than students who obtained lunch from off-campus. However, the average school-hour diet required improvement for all age groups, especially among older youth (14-17 year-olds). This study also found that age group moderated the association between lunch-time food source and dietary quality. That is, dietary quality did not vary significantly between lunch types in the younger age groups, but bigger differences in school hour dietary quality were observed among older children, which highlights the importance of considering children’s age when examining food source and diet quality. Overall school-hour diet quality was shown to need improvement among Canadian children. 

Implications

Food sources were associated with differences in school hour dietary quality, but only among children aged 9-17 years. Homemade lunches were slightly more nutritious compared to off-campus lunches, but overall, foods consumed by Canadian children during school hours require improvement regardless of food source. School-food strategies are needed to enhance access to nutritious foods on campus. Future interventions should also target lunch packing behaviours since the majority of Canadian students bring food from home to school.