Changes in the nutritional quality of products sold in university vending machines since implementation of the health star rating in 2014; an environmental audit

BACKGROUND: Snacking is a prevalent dietary behaviour among young adults, which could independently contribute to weight gain. Vending machines provide easy access to unhealthy snacks and beverages for young adults in universities. A voluntary front-of-pack labelling, named the Health Star Rating (HSR) system, has been implemented nationally by the Australian government as one strategy to address obesity since 2014. The primary aim of this study was to detect changes in the availability, pricing and advertising of healthy and unhealthy snacks and beverages in university vending machines after introduction of the HSR. METHODS: The study design was two cross-sectional audits of university vending machines one before (in 2014) and another after (in 2017) the implementation of the HSR. Data collections were conducted in a large urban university (> 60,000 students). Every machine was assessed; the product’s name, price, portion sizes and advertisements were recorded. Products were assigned an HSR to classify as healthy (≥3.5 stars) or unhealthy (< 3.5 stars). To compare the differences of product availability between 2014 and 2017, the Chi-square test was used. RESULTS: A total of 1836 and 2458 slots were audited in 2014 and 2017, respectively. The proportion of healthy snacks and beverages increased from 7 to 14% (p < 0.001) and 38 to 44% (p < 0.05) since 2014, respectively. The mean costs of unhealthy snacks and healthy beverages increased after three years. Healthy food and drink options were more expensive than unhealthy choices in 2017. Advertisements on vending machines for unhealthy foods and drinks remained prevalent. CONCLUSION: Only small changes have been observed in the availability of healthy snacks and beverages in vending machines since implementation of the HSR system. Policy directives are indicated to encourage further improvements.