A rapid review of the evidence for children's TV and online advertisement restrictions to fight obesity.

The World Health Organisation has urged all governments to address rising rates of obesity by implementing population-based interventions, such as restrictions on the marketing to children of unhealthy food and beverage items. However, the relationship between unhealthy food advertisements and childhood obesity is disputed by industry-sponsored reports, which recommend promoting physical activity and weight loss campaigns rather than policies to limit exposure to advertisements. We aimed to elucidate this debate by providing a narrative review of the evidence on the relationship between unhealthy TV and online food advertisements, short-term food consumption and childhood obesity. We also examined the impact of unhealthy food advertisements on vulnerable groups and identified which policy interventions are supported by current evidence. We conducted a rapid overview of reviews published since 2006. From a synthesis of 18 reviews meeting the inclusion criteria, we conclude that exposure to unhealthy TV and online food advertising is a contributing factor to childhood obesity. Evidence of a relationship between exposure to unhealthy food advertisements and childhood obesity was evident at all stages of the causal pathway, including a clear dose-response relationship. The evidence base was particularly strong for children aged 3-12 years of age and for children from socio-economically disadvantaged and minority ethnic backgrounds. The introduction of statutory regulation is a potentially cost-effective policy option, in terms of healthcare savings outweighing the costs of implementing the policy, although voluntary codes were shown to be ineffective, with exposure to unhealthy food advertisements similar in countries before and after their introduction. Food advertising, however, is just one factor in the wider obesogenic environment and further advertising restrictions must be implemented alongside population-based interventions that aim to address systemic causes of poor diet.