Introduced in February 2019 to help tackle childhood obesity in the capital, the policy has put advertising restrictions on advertising across the network, including the London Underground, the RfL Rail network, and at bus stops.Published in PLOS Medicine, a study from the London School of Hygiene and Tropical Medicine has now analyzed data on nearly two million grocery purchases of HFSS foods and drinks to estimate the effect of the policy.The researchers found that households purchased 1,000 less calories from HFSS products per week, a reduction of 6.