The current study is the first to evaluate youth dietary behaviours in relation to open-closed campus school policies in Canada. In a sample of 134 secondary schools in Ontario, Alberta, Quebec, and BC, only 16 schools reported CCP, in which students were not allowed to leave school property during breaks in the day. Consistent with our hypotheses, students at closed campus schools were more likely to eat snacks from school VMs, and less likely to drink SSBs (sodas/sports drinks or sweetened coffee/tea drinks) and to purchase lunch from a fast food or restaurant outlet on weekdays, than their peers attending schools with open campus policies. However, the likelihood of bringing a home-packed lunch to school, purchasing lunch in the school cafeteria, or eating snacks purchased from convenience stores or similar off-campus retail options, did not differ significantly based on attendance at open-closed campus schools. Therefore, while prospective studies are needed to examine within-student changes after policy implementation, cross-sectional results align with US evidence (30) suggesting CCP may help improve youth diets by preventing the external food retail environment from compromising school nutrition policies.
Given the increased likelihood of purchasing snacks from school VM on more days, but no association with the frequency of home-prepared lunches, CCP may lead only those students already purchasing food to shift from buying lunch at off-campus sources to options available for sale in schools. Consequently, the influence of the school food environment on student diets is likely heightened in closed campus schools. The Canadian Pediatric Society advises schools to limit food and beverages low in nutrients and high in calories, fat, sugar, and/or sodium (including fruit flavoured drinks, soft drinks, sports and energy drinks, and sweetened hot or cold drinks, including those with caffeine) (5). However, existing research indicates many schools are not compliant with nutrition policies in regards to the food and beverages offered for sale within cafeterias or VM (3, 37, 38, 39, 40). In Canada, with school food regulation purely market-based and restricted to within school sales, student access to external food retail options is recognized as a key barrier to healthful school nutrition environments (41); hence, CCP may serve to support policy adherence by reducing competitive sources that undermine financial-viability. Moreover, CCP represent a cost-effective intervention, with potential revenue gains for school cafeterias, and no expense to implement.
Results also suggest that spending money is the largest determinant of youth dietary behaviours on school days among the covariate and predictor variables considered. Students with any amount of money available for spending were less likely to bring a home-packed lunch and more likely to consume SSBs and purchase lunch or snacks from within-school or off-campus sources on more weekdays, than their peers without available spending money. Consistent with previous research (30), VM availability within schools was positively associated with students purchasing snacks from school VM. On the other hand, school drink VM were not associated with weekday SSB consumption, which may be expected given the regulation of SSB sales within schools, yet issues with compliance appear common (39). Previous studies have found greater SSB consumption in association with the availability of SSB (42) and sweetened coffee-tea drinks (19) in schools. No association resulted between the number of school snack VMs and student purchases of snacks from off-campus convenience stores and other retail options.
As expected with increased autonomy, students in higher grades were more likely to purchase lunch from outside sources on more days, and less likely to eat a home-packed or cafeteria lunch; however, contrary to expectations, they purchased snacks from convenience stores and external retail options on weekdays less often than grade 9 students. Unlike lunch, it is plausible that the weekday snacks were purchased before or after school. Purchasing behaviours outside of school hours may also explain the lack of association between CCP and snack purchases from convenience stores and similar retail off-school property. In contrast, Neumark-Sztainer et al. (2005) found students at suburban US schools with CCP during lunchtime were less likely to eat food purchased at convenience stores than students at open campus schools (30). Other researchers have noted that CCP would not be effective in preventing students from purchasing food at nearby food retailers before or after school (21). While this may be the case, particularly for snacks, these preliminary cross-sectional results suggest an overall reduction in SSB consumption and fast food lunches during the school week; and given that at least one-third of students’ total caloric consumption occurs during school hours (43, 44, 28), improving the lunchtime meal among youth has considerable potential to advance population nutrition.
Home-prepared lunches are generally associated with healthier diets than purchased options from either school cafeterias or fast food/restaurant outlets (26); however, prohibiting students from leaving campus does not appear to encourage more students to bring their lunch from home. In a recent photovoice study of high school students’ perspectives of food in schools, youth who brought a home-packed lunch perceived it to be a healthier, affordable, and convenient option that permitted autonomy; while students who went off campus to purchase food reported the proximity, low cost, space for social interaction, and perceived higher quality of food available as reasons (45). Youth voice a desire for healthier options at schools and being involved in the decision making about what types of foods are offered for sale in schools (45), which could be a critical consideration for policy implementation. Schools considering CCP should explore how they can engage students in the process.
Beyond food, students emphasize the importance of the places and spaces available to eat and socialize safely and comfortably during the lunch period (45). School cafeterias are considered loud and chaotic (45), with long lines to purchase food or use microwaves deterring intentions to stay at school for lunch (46). In response, some researchers have suggested changing the school timetables to staggered lunch hours and creating more youth friendly spaces outside (46). In fact, one reason for open-campus polices is to reduce cafeteria congestion during lunch hours (32). Schools with walkable neighbourhoods and food retailers in close proximity are more likely to have open campuses (47). Another motive is to support adolescence autonomy and independence. In US schools that changed to open campus environments, grade 11 and 12 students felt more control over their environment than their peers at closed campuses; however, some students also reported disciplinary problems, poorer grades, less school spirit, and reductions in their social life both in and out of school (48). Future research is needed to compare positive and negative effects of school open and CCP on various behavioural, social, mental, and academic outcomes to inform best practices moving forward.
Strengths and Limitations
A key strength of this study is the large sample size, with data at both the student- and school-levels in varied school contexts in four Canadian provinces. While these factors support generalizability, the COMPASS study was not designed to be provincially or nationally representative and uses a convenience sample. Relatedly, additional confounders not controlled for may contribute to differences in schools with and without CCP and students attending these schools. For instance, while school area urbanicity, province, and median household income, and the number of within school VM, are controlled for, the current study does not account for differences in the food environment surrounding schools. The primary limitations of the current study are the use of cross-sectional data and self-reported dietary measures. Future studies should further examine CCP using prospective data and quasi-experimental natural experiment designs to test whether students transition from purchasing food off-campus to purchasing food within the school after a CCP is implemented. Student reported dietary behaviours and school administrator-reported policy measures introduced possible recall and social desirability biases. Also, the dietary measures are limited to assessing the number of days that students engaged in the dietary behaviour indicated, and do not account for the number of times per day (e.g., the SSB measures assess the number of weekdays that students consume SSB but do not indicate if students drink multiple SSBs in a day). Lastly, the measures for snacks purchased from off-campus retail and SSB assess weekday consumption/purchasing, but do not indicate when during the day (i.e., during school hours, or before/after school); however, overall weekday consumption is more important to determine full nutritional impact.