London transport junk food advert ban has prevented 95,000 obesity cases, study suggests

A ban on junk food advertising on Transport for London (TfL) networks is estimated to have prevented almost 100,000 obesity cases, a new study says.

The rule restricts the advertisement of foods high in calories from sugar and fat or high in salt.

The study, published in the International Journal of Behavioural Nutrition and Physical Activity, estimates the policy which has been in effect since 2019 has directly led to 94,867 fewer cases of obesity than expected – a 4.8 per cent decrease. It also estimates that the policy will have led to 2,857 fewer cases of diabetes and 1,915 fewer cases of cardiovascular disease.

Research conducted by the University of Sheffield and the London School of Hygiene & Tropical Medicine (LSHTM) claims that the policy could save the NHS £218m 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.

Their findings showed 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”.

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.”

However, some commentators have taken issue with the methodology used by the study .

This article was amended on 4 August 2022. It previously said that the study showed the advertising ban had reduced levels of obesity, diabetes and cardiovascular disease. However, the research did not do this but instead quantified what researchers believed were the likely effects of the ban based on modelling. We also added the fact that some commentators had taken issue with the study .