Healthy vending machines on campus: the effect of traffic light labelling on food and beverage choices

Objective: To investigate whether the introduction of healthy vending machines on a university campus could increase the proportion of healthy food and beverage purchases. 

Design: Four new healthy vending machines offering a wider range of healthier food and beverages were installed alongside existing machines. These new machines used traffic light colours to indicate nutritional value. A year after their installation, a traffic light text guide and colourful wrap were added to the new machines. χ 2 tests were used to assess significant differences in the sales of green (healthy), amber or red (unhealthy) items from healthy and existing vending machines across the 3 years (2021-2023). 

Setting: The study was conducted on a university campus where the new healthy vending machines were installed. 

Participants: Participants of this study were the consumers who purchased items from the vending machines on the university campus. 

Results: The results indicated a shift towards healthier purchases following the introduction of the healthy vending machines. The addition of the traffic light text guide and colourful wrap further reduced unhealthy purchases, although this change was small. Sales from the existing vending machines did not meaningfully decrease, and any reductions were more than replaced by sales from the new healthy vending machines. 

Conclusions: The study concluded that by providing healthier options and guiding consumers towards these options, the vending machine programme offers a promising pathway towards promoting healthier food and beverage choices from vending machines on university campuses.