Page 34 - ON THE WAY TO HEALTHIER SCHOOL CANTEENS - Irma Evenhuis

Chapter 2. Study protocol
based on literature [112]. We hypothesize that students in the intervention group will
achieve a healthier purchase behaviour.
After the intervention period, differences in the secondary outcome ‘health level’ of the canteen between the intervention and control schools will be investigated with descriptive statistics. Thereafter, to gain insight into the effect of the health level of canteens and purchase behaviour of students, we will include the health level of canteens in a per protocol analysis. This model will be built similar as the explained intention-to-treat analysis. All information is being gathered with rigor, so these analyses will show which factors make a difference in student behaviours, including implementation features. We hypothesize that intervention schools will improve their health level of the canteen, and that a healthier canteen will lead to healthier purchases. Statistical analyses will be performed using the IBM SPSS statistics version 24.0. MLwiN 2.36 software will be used to conduct the multilevel regression analyses. For all statistical analyses, a two-tailed and 5% significance level will be applied [110].
DISCUSSION
This study design describes how we developed and will evaluate a plan to implement guidelines to create healthier canteens in secondary schools using a systematic theory and practice-based approach. The study aims to contribute to a feasible and effective implementation of healthier school canteen policy in secondary schools. We hypothesise that schools which will receive support to implement the guidelines, will offer healthier food and beverages and that these products will be more easily accessible in the canteens compared to schools that will not receive support. In addition, we hypothesize that this will be associated with healthier purchase behaviour of students in intervention schools.
Implementation of policy to limit the availability of less healthy food in schools is recommended [88] and seems effective [89]. However, it also faces challenges, like conflicts with time demands for other school activities, different interests of the stakeholders (e.g. financial profit vs. healthiness), or that the implementation materials will not be used as intended. These challenges may influence the feasibility and the effectiveness of the implementation process. Although these challenges will always be present, the involvement of stakeholders during the development phase and the combination with evidence-based knowledge, frameworks and behaviour change methods will result in a plan that effectively intervenes on identified challenges [58, 90]. Also, the proper process evaluation will inform us about the extent of these issues. Based on all knowledge this research creates, we are able to further improve the implementation plan.
A strength of this study is the involvement of stakeholders from research, policy and practice, which increases the support for and feasibility, usability and impact of the intervention [52, 86, 91]. As recommended, stakeholders were included in the development of the implementation plan and will be asked to share their experiences during implementation, in order to adapt the implementation tools if required [92]. Acknowledged by Shea et al. it is important to have specific competencies to participate in community-engaged dissemination and implementation research [113]. In the past years, the school canteen
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