This study is one of very few that examined the impact of both nutrition and physical activity school guidelines on the school environment. Results demonstrate that after BC schools were expected to implement the food and beverage guidelines and daily physical activity requirements, schools decreased their availability of less healthful food and beverages and increased the number of minutes of PE offered per week, based on principal report. These changes are encouraging and similar to the policy impacts found in other jurisdiction [18–21]. Further evaluation to determine if these policies will impact student behaviors is warranted.
Change in school nutrition environment
The FBSS guidelines resulted in significant changes to the school food environment but impacted elementary and middle/high schools differently. Differences may be partly explained by the amount of food and beverages available at school to start with [4, 20]. Overall, middle/high schools decreased the availability of less healthful food and beverages whereas elementary schools decreased the availability of less healthful beverages and significantly increased the availability of fruits and vegetables at school. The increase in fruits and vegetables was somewhat unexpected since the guidelines did not mandate schools to offer more healthy options but may be the result of the government scaling up provincial programs that targeted elementary schools over this time period such as the fruit and vegetable program that included bi-weekly delivery, raising awareness of local produce, ‘tasting’ activities, and materials for teachers, and a whole school physical activity and healthy eating initiative that provided technical support and resources to teachers that were attempting to implement classroom healthy eating practices .
Overall, nutritional environment changes in elementary and middle/high schools were all in the expected direction. With the exception of the availability of pizza, hamburgers and hotdogs and availability of 100% fruit juices (only in middle/high schools), the guidelines seem to have targeted the appropriate food and beverage items. It is not surprising that the availability of pizza, hamburgers and hotdogs did not change over time because the guidelines allowed reformulation of these products as opposed to restriction. Reformulations focused on improving grains and reducing fat, sodium and additives rather than increasing vegetables. Indeed, we found that after implementation of the guidelines a large proportion of schools (>50%) were serving these items with whole grains. If children continue to eat only these reformulations, the guidelines might fall short in increasing children’s consumption of vegetables at lunch time. Furthermore, elementary schools significantly decreased the availability of 100% fruit juice while middle and high schools significantly decreased the availability of sugar-sweetened beverages but not 100% fruit juices where availability remained high (94%). Although 100% fruit juice was not targeted by the guidelines, it may have been used to replace sugar-sweetened beverages in middle/high school vending machines. When consumed in appropriate portions, 100% fruit juice is not problematic;  however, large servings of 100% fruit juice have been suggested as a potential contributor to children’s positive energy balance [35, 36]. Continued monitoring of such policies is essential to ensure that consumption of sugar-sweetened beverages is not replaced by consumption of inappropriate portions of 100% fruit juice.
Many schools reported that they continue to struggle with making changes to their food environment. Implementation was particularly low for fundraising activities and special events among both elementary and middle/high schools as well as for cafeterias among middle/high schools. As we discovered from in-depth interviews with school principals and teachers in 2010–11, fundraising activities and special events may be particularly challenging areas for schools to make changes since access to healthier alternatives are lacking and there is a potential for lost revenue . In addition, school informants reported that perceived value, compatibility with school mandate/teaching philosophy, observable positive impacts, and availability of resources promoted implementation while the complexity of guidelines impeded implementation. Previous studies have also reported that schools experience a variety of barriers to implementation including funding, competing priorities and support from stakeholders . Furthermore, a Canadian study identified lack of support, complexity of guidelines, and a top-down approach as barriers to implementation . A key area of future research needs to be in improving implementation as gaps in implementation likely result in reduced policy effectiveness.
Previous studies have also reported favorable changes to the school food environment after implementation of state or federal policies/guidelines [19, 21, 38]. A cross-sectional examination of the strength of state nutrition policies found that elementary and middle schools with state policies restricting junk food had lower availability of junk food in vending machines and school stores, with no change in high schools . This result differs from the current study, where we found declines in less healthful food among middle/high schools but not elementary schools. In another study, records of all food served for lunch were collected for the years before and after implementation of the Texas nutrition policy and revealed that fewer fried vegetables (French fries) were served for both elementary and high schools, but no change was observed for regular vegetables, fruit or milk . Using a similar design as the current study, comparison before and after the implementation of Maine’s state-wide nutrition policy banning “foods of minimal nutritional value” found that the availability of soda, but not other junk foods, declined in high schools . In contrast, we observed declines in various less healthful food products including junks food, along with declines in sugar-sweetened beverages. Despite the encouraging changes within the BC school food environment, many schools continued to serve refined grains and other less healthful food and beverages.
Change in school physical activity environment
After the DPA policy was put into place, schools increased minutes of PE per week for grade 6, 8, and 10 students. Unlike most US state policies, the BC guidelines were not specific about increasing PE time but instead allowed schools choice in how to increase physical activity. In elementary schools, schools could meet the guidelines by implementing the Action Schools! BC initiative that was supported by the province. A key strategy of Action Schools! BC was to increase physical activity breaks in the classroom [39, 40]. While the DPA guidelines did not directly target PE time, we found that many schools opted to increase PE time to meet the provincial guidelines. This finding is corroborated by results from our qualitative study that examined (among others) strategies schools used to implement the DPA guidelines . Our data did not allow for comparison of the impact of the two approaches in achieving the guideline. In the province of Ontario, where a similar DPA policy was mandated in 2005, a cross-sectional study using accelerometry reported that 5-years into implementation of the policy, the majority of students were not active on every school day and no child met sustained activity for 20 minutes at one time, suggesting that schools were not meeting the guidelines . Further investigation is required to investigate the relative value of a DPA guideline versus a daily PE guideline.
In the current study, schools also changed their delivery method of PE from semester to linear for grade 8 students, while the opposite occurred for grade 10 students. This is a puzzling finding. We had hypothesized that schools might move towards a linear system to deliver PE (shorter bouts spread out over the whole year); however, this finding aligns with our qualitative interviews that suggest schools are challenged with fitting activity into a very busy school schedule . This did not seem to be the case for students in grade 10. Unlike in grades 6 and 8, PE in grade 10 is a graduation requirement. Perhaps more grade 10 schools opted to increase physical activity classes and as a result offered PE on a semester system which is easier to accommodate in the schedule given that all other academic courses are on a semester system.
Although the guidelines examined in the current study were not specific to PE, several US studies have reported similar positive changes to PE time after implementation of PE-specific policies [24, 25]. A study of elementary schools found that schools were more likely to meet the recommended 150 minutes per week of PE once the state policy was in place . In another study of middle/high schools, minutes of PE per week increased by 18 minutes for grade 8 students and 11 minutes for grade 10 students. Increased minutes of PE time also occurred after policy implementation in US high schools . These increases are meaningful as a recent study found that students did not compensate by being less active at home; thus, school PE increased their overall physical activity levels .
Change in school community support for healthier guidelines
The successful changes made by schools in this study occurred concurrently with increased support from the school community for healthier eating and physical activity. Greater support by school community has previously been identified as key component to successful implementation of school policies/guidelines [26, 27, 43]. Increases in staff and parent support were consistent across school and guideline type suggesting that support from these two groups is important for fostering change. In general, support increased more for physical activity policies than healthy eating policies. This may be a consequence of the differing implementation context. Changes in DPA are largely the responsibility of the teacher and have no impact on fundraising while changes in food policies involve parents and affect fundraising. In addition, the lowest increase in support for healthy eating was among middle/high school students, where support was also lowest at baseline. Restrictions on food may be particularly unpopular among this age group as they are developing independence and have access to choices off school property when schools do not provide them [26, 44]. There was no change in policy support by the principal; however, they also had self-reported the highest level of initial support for both healthy eating and physical activity across school types.
Although this study focused on the implementation of guidelines within the BC context, similar policies are being adopted in other jurisdictions making these findings relevant to other settings. This study was limited to mostly principal reports of the school environment which may be influenced by social desirability bias, unmeasured characteristics of the respondent, or differences in respondents at each time point. However, our self-report showed some validity as associations between implementation and school environment were in the expected direction (higher implementation significantly associated with less unhealthy food and beverages and more PE minutes - data not shown). While we acknowledge the limitations of self-report, studies that are able to utilize objective measures such as food purchasing data or direct observation of school cafeterias may find different results. Importantly, some changes were made as to how the questions were asked at each time point; this specifically pertains to the PE questions (see the Methods section). Every effort was made to treat data in a way that enhanced comparability over time but it is possible that changing the questions influenced the results as principals may have interpreted the question differently. Our analysis incorporated cross-sectional samples at each time point which may have contributed to bias in our findings. This impact is likely minimal since our results are stable with and without the inclusion of the cross-sectional samples (see Methods section). Furthermore, an important limitation of natural experiments is that we cannot control for other concurrent school, community or provincial programs that may contribute to observed changes in the school environment. As there were provincial initiatives targeted at elementary schools during our evaluation period, the changes observed in elementary schools may have been attributed to both the enactment of the FBSS or DPA guidelines and support provided for these initiatives. Finally, we did not examine changes in student level behaviors; however, this will be an important component of future policy evaluations, particularly in light of evidence that suggests increases in PE time may results in decreased forms of other school-based physical activity, such as at recess,  and that students may turn to food and beverages available off school property if they can’t get them at school [26, 44]. Despite these limitations, this study capitalized on a natural experiment with data collected before and after full implementation of guidelines were expected, providing a rare opportunity to demonstrate policy impact at the school-level.