Improving healthy eating in schools
Many adolescents have poor eating habits and struggle with overweight. As much as 50% of their calories are consumed at school, so a change in the school environment can have a big influence.
In this study, we aimed to find whether putting more healthy items on display would increase the sale of healthier products. The assortment of products remained the same, but instead of having 60% of the items visible on sale being ‘healthier choices’, 80% of the visible products were healthier choices. Although students could still buy unhealthier products, these made up only 20% of the visible assortment, possibly making it more attractive for students to select from the majority of healthy products.
The second aim of this study was to find if there would be a difference in sales of healthier products if we increased the visible healthy assortment abruptly or gradually. Two canteens participated in this study, both starting with a baseline of 60% healthier items on display. In the first canteen, there was an abrupt change to 80% healthier products on display. The second canteen had a phase in between 70% healthier products on display, and then 80% after a few weeks.
To answer these questions, we used both the sales data and questionnaires. The sales data were for both healthier and unhealthier choices of food and drinks products. The surveys were conducted multiple times throughout the year, asking students about their satisfaction with the canteen and their eating habits at school.
What we’ve all been waiting for: Results
The results show that the proportion of healthier products sold increased from 31.1% during the baseline period to 35.9% in the final period. This means there was an effect of increasing the visible share of healthier products, but it was not a very large difference from before. There was a noticeable difference between product groups. Especially beverages and sandwiches showed a larger increase. The canteen that gradually increased its assortment to a healthier display, sold a larger share of healthier products than the canteen that abruptly changed its assortment. The students were moderately satisfied with their canteens, and this did not change throughout the experiment.
Overall, results suggest that increasing the availability of healthier products in school canteens leads to small positive changes in sales of products, particularly in the product groups beverages and sandwiches. A gradual introduction may ensure that students slowly get used to assortment changes.
Read our paper: van Kleef, E., Kremer, F., & van Trijp, H. (2020). The Impact of a Gradual Healthier Assortment among Vocational Schools Participating in a School Canteen Programme: Evidence from Sales and Student Survey Data. International Journal of Environmental Research and Public Health, 17(12), 4352.
Or have a look at the entire Infographic study (thanks to piktochart.com)