Restricting the outdoor advertising of high fat, salt and sugar (HFSS) foods and drinks across the Transport for London (TfL) network is estimated to have significantly decreased the average amount of calories purchased by households every week from these products, according to new research in PLOS Medicine.
Led by the London School of Hygiene & Tropical Medicine (LSHTM), the study used data on nearly two million grocery purchases of HFSS foods and drinks to estimate the effect of the policy, which saw restrictions on advertising across the TfL including the London Underground, the TfL Rail network, and at bus stops.
It found households purchased 1,000 less calories from HFSS products per week, a reduction of 6.7%. Chocolate and confectionery saw the sharpest decrease with weekly purchases falling by 318 calories, a 20%reduction. Overall, Londoners were on average buying the equivalent of just under one and a half milk chocolate bars less per week.
The researchers also found some limited indication that effects were larger in households with obese individuals.
Dr Amy Yau, from LSHTM and study first author, said: “Many governments and local authorities are considering advertising restrictions to reduce consumption of high fat, salt and sugar (HFSS) products as part of obesity prevention strategies. However, evidence of the effectiveness of such policies, especially away from broadcast media, is scarce.
“Our study helps to plug that knowledge gap, showing Transport for London’s policy is a potential destination for decision-makers aiming to reduce diet-related disease more widely.”
The junk food advertising restrictions were introduced in February 2019 to help tackle child obesity in the capital. Then, 38.2% of 10 to 11-year-olds in London were overweight or obese when the policy was introduced in 2019. According to the NHS, that figure soared to 45.2% in 2020, the biggest rise seen in the country. Campaigners have however blamed this rise on lockdowns and school closures.
Dr Camilla Kingdon, President, Royal College of Paediatrics and Child Health, said: “We’ve seen a sharp rise in childhood obesity over the pandemic with children in the most deprived communities hardest hit. Given the far-reaching health effects of obesity, this stores up huge problems for the future and further widens unacceptable health inequalities."
The study comes as the Health Bill goes through UK Parliament. This will ban unhealthy food from being advertised online and before 9pm on TV by January 2023.
“These results show the welcome impact restrictions on junk food marketing can have. Nationally, it is important that the UK Government remains committed to a ban on junk food marketing with a 9pm watershed on TV and a total ban online,” added Kingdon.
The study’s authors acknowledged limitations of the study, including that it was focused on products to take home (grocery purchase) and did not include takeaway purchases from fast-food outlets, restaurants, cafes etc. Effects may well be larger if takeaway purchases had been included, they claimed.
Professor Steven Cummins, from LSHTM and Chief Investigator of the study, said: “The impacts we observed are larger than those reported for the UK Soft Drinks Industry Levy, those predicted for a 9pm advertising watershed on HFSS foods or a 20% tax on sugary snacks.
“The findings are particularly significant in light of the Health Bill currently going through Parliament, as they provide further evidence for the effectiveness of advertising restrictions and help support the case for the Government’s proposed ban on the online advertising of high fat, salt and sugar foods and drinks.”
The team said that while the results are encouraging, the findings are in the context of actual increases in purchases of HFSS products in intervention and control areas over the study period, meaning intervention was effective in reducing growth of HFSS purchases rather than achieving absolute reductions in HFSS purchases.
Professor Cummins said: “More work is needed, but our study suggests these types of policies could have a significant impact on reducing consumption of high fat, salt and sugar foods, and offer a potentially effective intervention in other important public health policy areas such as the regulation of alcohol and gambling advertising.”
The Mayor of London, Sadiq Khan, said: “It is a scandal that London has such high levels of child obesity and, that in a city as prosperous as ours, where you live and the amount you earn can have such a huge bearing on whether you have access to healthy and nutritious food.”
Michelle Mitchell, Cancer Research UK’s chief executive, added: “This research joins numerous other studies that show restrictions to junk food marketing are a useful tool in reducing obesity – the second biggest preventable cause of cancer. I urge the Government to listen to the evidence and fully commit to its ‘war on cancer’ by introducing their planned national restrictions to junk food advertising and promotions as soon as possible.”
