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

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. χ2 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).

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

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

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.

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.

To test whether traffic light labels and an increased range of healthy beverages, individually and in combination, can increase healthy beverage choices from vending machines.

Two studies (n 558, 420) tested whether the provision of traffic light labels (green, amber and red) and an increased range of healthy beverages (from 20 % to 50 % green options), individually and in combination, could increase healthy beverage choices from a digital vending machine display. The studies used a between-subjects experimental design, and a hypothetical beverage choice, a limitation when considering real-world applicability.

Both studies utilised an online Qualtrics survey that featured a digital vending machine display.

Both studies (n 558, 420) consisted of university students from Flinders University and individuals from a survey recruitment service.

Featuring traffic lights did not significantly influence beverage choices (P = 0·074), while increasing the healthy range (P = 0·003, OR = 3·27), and the combination of both, did significantly increase healthier beverage choices (P < 0·001, OR = 4·83).

The results suggest that the traffic light system and increased healthy range are not maximally effective when used on their own, and benefit greatly when combined, to increase healthy beverage choices. It was suggested that the provision of traffic light labels supplied the necessary nutritional information, and the increased healthy range offered greater opportunity to act in accordance with that information. In so doing, the present findings offer a promising pathway for reducing unhealthy beverage consumption.