Increased marketing of energy-dense, nutrient-poor foods has been identified as a driver of the global obesity epidemic and a priority area for preventative efforts. Local and international research has focused on the unhealthiness of television advertising, with limited research into the growing outdoor advertising industry. This study aimed to determine the level of public exposure to unhealthy food and beverage advertising on the Sydney metropolitan train network.
All 178 stations on the Sydney metropolitan train network were surveyed in summer and winter. A survey tool was developed to collect information on the product, brand, location and size of all advertisements on and immediately surrounding the train station. Food and beverage advertisements were coded by nutrition category (core, discretionary, miscellaneous) according to the Australian Guide to Healthy Eating. Chi-square, ANOVA and ANCOVA tests were conducted to test for differences in the amount of food advertising by season and area socioeconomic status (SES).
Of 6931 advertisements identified, 1915 (27.6%) were promoting a food or beverage. The majority of food advertisements were for unhealthy products (84.3% discretionary; 8.0% core and 7.6% miscellaneous). Snack foods and sugar-sweetened beverages were the most frequently advertised products, irrespective of season. Coca-Cola and PepsiCo were the largest advertisers on the network, contributing 10.9% and 6.5% of total advertisements respectively. There was no difference in the mean number of food advertisements by area SES, but the proportion of advertising for discretionary foods was highest in low SES areas (41.9%, p < 0.001).
The results indicate that food and beverage advertisements across the Sydney metropolitan train network are overwhelmingly for unhealthy products, particularly in low SES areas. This study highlights the inadequacy of Australia’s voluntary self-regulatory system in protecting members of the public from exposure to unhealthy food advertising, and the need for regulatory action by government.