The advertising policy, which has been in place since 2019, could save the NHS more than £200 million, researchers claim.
They estimate the policy has directly led to 94,867 fewer cases of obesity than expected (a 4.8 per cent decrease), 2,857 fewer cases of diabetes, and 1,915 fewer cases of cardiovascular disease.
The rule restricts the advertisement of foods high in calories from sugar and fat or high in salt.
The analysis from the University of Sheffield and the London School of Hygiene & Tropical Medicine (LSHTM) estimated the policy would save the NHS £218 million over the lifetime of the current population.
Academics assessed the effect of the policy by seeing what consumers are purchasing in their weekly food shops via surveys, and comparing trends in London to a control group of households outside of London where there were no restrictions on advertising in place.
They said their findings show the policy has had the biggest impacts on people from deprived areas in terms of preventing health conditions.
Despite people on middle incomes cutting more calories, researchers claim the policy has had a bigger impact on the most deprived areas as “people from those areas tend to be less healthy overall”.
The study is published in the International Journal of Behavioural Nutrition and Physical Activity.
Dr Chloe Thomas, first author of the study from the University of Sheffield’s School of Health and Related Research, said: “We all know how persuasive and powerful advertising can be in influencing what we buy – especially the food we eat.
“Our study has shown what an important tool advertising restrictions can be in order to help people lead healthier lives without costing them more money.
“We hope that demonstrating the policy’s significant benefits in preventing obesity and the diseases exacerbated by obesity will lead to it being rolled out on a national scale.”