Effectiveness of a multicomponent intervention to enhance implementation of a healthy canteen policy in Australian primary schools: a randomised controlled trial.

BACKGROUND
The implementation of school nutrition policies, which govern the provision of food in schools, is recommended as a public health strategy to support the development of healthy dietary behaviours in school-aged children. Despite this, research internationally and in Australia indicates that few schools implement such policies. This study aims to examine whether a theoretically designed, multi-strategy intervention was effective in increasing the implementation of a healthy canteen policy in Australian primary schools.

METHODS
A parallel group randomised controlled trial was conducted with all government and Catholic primary schools within one region in New South Wales, Australia who had an operational canteen that provided food to primary school aged children (5-12 years) and were not currently receiving an intervention to change their canteen practices. Schools randomised to the intervention arm received a 9-month multicomponent intervention including ongoing support, provision of resources, performance monitoring and feedback, executive support and recognition. The primary outcomes were the proportion of the schools with a canteen menu that: i) did not include 'red' or 'banned' items according to the healthy canteen policy; and ii) had more than 50 % 'green' items. The primary outcome was assessed via menu audit at baseline and follow up by dietitians blinded to group allocation.

RESULTS
Fifty-three eligible schools were randomised to either the intervention or control group (28 intervention; 25 control). Analyses with 51 schools who returned school menus found that intervention schools were significantly more likely relative to control schools to have a menu without 'red' or 'banned' items (RR = 5.78 (1.45-23.05); p = 0.002) and have at least 50 % of menu items classified as green (RR = 2.03 (1.01-4.08); p = 0.03).

CONCLUSIONS
This study found that a multi-component intervention was effective in improving primary schools' compliance with a healthy canteen policy. Given the lack of evidence regarding how best to support schools with implementing evidence-based policies to improve child diet, this trial for the first time provides high quality evidence to practitioners and policy makers seeking to improve nutrition policy implementation in schools.