Page 88 - ON THE WAY TO HEALTHIER SCHOOL CANTEENS - Irma Evenhuis

Chapter 5. Effect evaluation
h Model 4 = Model 3, plus corrected for environmental determinants (amount of money spent in school p/w, breakfast, food purchases outside school, drink purchases outside school, food brought from home, drinks brought from home).
DISCUSSION
We investigated the effect of support in implementing the “Guidelines for Healthier Canteens” on changes in the school canteen (cafeteria and vending machine) and in food and drink purchases of students. Our results show that the support has led to actual changes in the availability and accessibility of healthier products in the canteen. We did not observe changes in students’ purchase behaviour. The large majority of the students (90%) reported that they usually bring food or drinks from home. Most (approximately 80%) students reported buying food or drinks in school only once a week or less.
Schools that received support showed a larger increase in the availability of healthier prod- ucts in the cafeteria compared to control schools. The intervention schools also complied with more criteria for the accessibility of healthier products than the control schools. These results are in line with previous studies which also showed that implementation support is likely to increase the use of guidelines, especially if it consists of multiple components and is both practice and theory-based [56, 60]. The support we offered was targeted at different stakeholder-identified impeding factors related to implementation of the guide- lines, such as knowledge and motivation. The process evaluation already showed that our implementation plan favourably influenced these factors [132].
With regard to vending machines, changes were smaller and present in fewer schools compared to changes in the cafeteria. This result may be explained by the fact that schools do not always own nor regulate the content of the vending machines themselves, but outsource them to external parties such as caterers or vending machine companies. Some schools were therefore unable to change the offering and position of products in the machine within the study period. Previous research showed that vending machines were healthier if appointments about the healthy offer were included in agreements with caterers or vending machine companies [188]. Making agreements about the availability and accessibility of healthy products in the machines is therefore recommended.
In contrast to the changes in the canteen, we did not observe relevant differences in change of healthier purchases between students in intervention and control schools, nor between students from schools with a healthier canteen compared to students from schools with a less healthy canteen. An explanation for these results might be that the duration of the intervention was between four to six months, which proved to be short for the schools to make changes, as we noticed that in most canteens changes were made just before the post-measurements. As a result, students did not have enough time to get used to the new situation and to adapt their purchases. The effects of a healthier canteen on students’ purchases remain therefore unknown. Our results are in contrast with many other studies that show that increasing the offering of healthier products and changes in placement and promotion in favour of healthier products are likely to lead to healthier food choices among customers [21, 25, 42, 43, 45]. However, reviews identified that investigations yielded contradictory results [49], and they emphasize the low quality of the studies [45],
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