Abstract:
Background Unhealthy food advertising is a risk factor for childhood obesity. The World Health Organization (WHO) published a set of recommendations for countries to implement policies to restrict unhealthy food advertising to children. However, few studies have evaluated these policies and no studies have assessed the impact of the updated 2017 New Zealand Advertising Standards Authority (ASA) code. Aim The overall aim of this thesis was to evaluate the impact of current international policies to reduce unhealthy food advertising to children on virtual platforms. Method A systematic review of international literature was completed across four scientific databases to examine the impact of policies to restrict unhealthy food advertising to children on virtual platforms. New Zealand data on children’s television viewing patterns and recordings from 2015 and 2018 were analysed. The healthiness of food advertisements was coded using three nutrient profiling models and children’s exposure to unhealthy food advertising was compared between the years. Results The systematic review (n=20 studies) suggested that mandatory policies were marginally more effective at restricting unhealthy food advertising to children than self-regulatory policies. There was a decrease in the number of children watching and exposed to unhealthy food advertising on New Zealand television between 2015 and 2018, and thus a significant reduction in impact. However, the percentage of food advertisements that were for unhealthy food in both 2015 (75.9% on weekdays and 76.3% on weekends) and 2018 (63.7% on weekdays and 65.9% on weekends) was over 50%. Conclusion Mandatory policies were slightly more effective than self-regulatory policies in the systematic review. After the New Zealand ASA code update, there was a decrease in children exposed to unhealthy food advertising on television (fewer children watching and less unhealthy food advertisements). But unhealthy foods still made up two-thirds of all food advertisements. Thus, there is a need for mandatory policies, stronger definitions of ‘children’ and ‘unhealthy food’, and regular monitoring and evaluation on the internet and social media to hold food companies more accountable in advertising.