Effect of a vegetable-focus in primary school canteen menus on vegetable sales: a randomised controlled trial

This study aimed to determine the effectiveness of an 8-week multi-strategy behavioural intervention that included vegetable provisioning and online menu architecture on vegetable sales in primary school canteens. A randomized controlled trial was undertaken in 16 Australian primary schools (n=4302 students). The control arm kept their regular canteen menu. The main outcome was vegetable sales measured by assessing vegetable content (in grams) from all menu items and using canteen sales (ordered online and over-the-counter) to calculate vegetable sales (in g/wk) before the intervention (for 3 weeks) and while the intervention was implemented (for 8 weeks). Other outcomes were vegetable sales in subcategories, acceptability of the intervention among canteen managers and vegetable waste (4 schools). Analysis showed that the intervention group had higher weekly vegetable sales overall compared with the control group (average increase of 2707g/week), with increased vegetable sales in the subcategories of burgers, hot foods and snacks, but not in sandwiches and pasta/rice dishes. The intervention did not lead to more vegetable waste, nor to a decrease in canteen revenue. The canteen managers found the intervention easy to implement and felt children responded favourably to three of the seven strategies. In conclusion, a multi-strategy behavioural canteen intervention increased vegetable sales amongst primary school students.