Junk food ad restrictions: health remedy or junk science?

By Oliver Morrison contact

- Last updated on GMT

Image:Getty/Bonfanti Diego
Image:Getty/Bonfanti Diego

Related tags: Obesity, HFSS, Junk food marketing

Junk food advertising restrictions on Transport for London (TfL) networks have prevented almost 100,000 obesity cases and are expected to save the UK’s National Health Service over £200 million, according to new research that critics have accused of using ‘flawed methodology’ and ‘misleading modelling'.

The study revealed the TfL advertising policy restricting the advertisement of foods high in calories from sugar and fat or high in salt (HFSS), has led to consumers cutting down on less healthy products.

Researchers estimated the policy, which has been in place since 2019, 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 analysis further claimed the current advertising policy would save the NHS £218 million over the lifetime of the current population.  

The study is published in the journal International Journal of Behavioural Nutrition and Physical Activity​, and led by the University of Sheffield in collaboration with researchers from the London School of Hygiene & Tropical Medicine (LSHTM), who previously found the advertising policy has contributed to a 1,000 calorie decrease in energy from unhealthy purchases in consumers' weekly shopping​. 

To study the effect of the TfL policy the researchers looked at the weekly shops of 1,970 households (with households having an average of 2.6 individuals) from London and the North of England (where there were no restrictions in place), each of whom recorded all food and drink items purchased and brought into the home. 

Dr Chloe Thomas, First Author of the study from the University of Sheffield’s School of Health and Related Research (ScHARR), 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, something that could save lives and NHS money."

The researchers further claimed their findings show the policy has had the biggest health impact on people from deprived areas, despite those people on middle incomes cutting more calories. That’s because “people from those areas tend to be less healthy overall”​, they stated.

Dr Penny Breeze, Lead Investigator of the study from the University of Sheffield’s School of Health and Related Research (ScHARR), added: “There have been very few studies that have looked at the health and economic impact of out of home advertising restrictions. We are delighted to show that there are many benefits to the policy, and hope that the policy continues to be rolled out outside of London.”

The Mayor of London and Labour party politician Sadiq Khan said: “Advertising undoubtedly plays a significant role in promoting and encouraging the consumption of less healthy foods. With child obesity putting the lives of young Londoners at risk it simply isn’t right that children and families across the capital are regularly inundated with adverts for foods that do not support their health – that’s why I was clear that tough action was needed.

“This study, which builds on research from earlier this year, demonstrates yet again that the ground-breaking restrictions we introduced could not only influence behaviour and ultimately save lives but could directly save our NHS hundreds of millions of pounds.”

This is dodgy research’

But critics claimed the research is based on 'flawed methodology which uses misleading modelling'.

Emma Best, GLA Conservatives Health spokesperson, said: “With rising childhood obesity in London, amongst reception and year 6 children, it is brazen for the Mayor to claim success on the basis of junk science which has been roundly and repeatedly debunked.”

“With up to £25 million in lost revenue and a flawed and inconsistent roll-out of this policy, Londoners rightly expect the Mayor to stop pushing dodgy research to cover up his mistakes and start taking serious action to improve the health of London’s children.”

Christopher Snowdon, Head of Lifestyle Economics at free market think tank the Institute of Economic Affairs, pointed out the study uses the Kantar Fast Moving Consumer Goods data, which does not include restaurant meals, fast food, snacks bought outside the home. That’s significant both because a large amount of HFSS food is bought out of home and was the type of food item typically advertised on TfL before the restrictions came in place.   

The LSHTM researchers have previously claimed the effects they saw may well be larger if takeaway purchases had been included.

Snowden however rubbished claims that London households ate 1,000 fewer calories of HFSS after the ban. The study authors “could only pretend it was true by creating a ridiculous counterfactual in which consumption rose sharply for no reason if there hadn't been a ban," ​he tweeted.

The study data, for instance, show that both sets of households reduced their HFSS food purchases and overall calories in the period after the TfL ban was introduced. It was only in the 'puddings and biscuits' category where a noticeable difference was seen in consumption between Londoners and the control group – not items generally associated being advertised on tubes, buses and trains.

In a IEA statement, Snowden added: “This modelling study is one of the worst pieces of junk science I have ever come across in a journal. It builds on an earlier modelling study which falsely claimed that the advertising ban caused Londoners to consume 1,000 fewer calories a day and makes various back-of-the-envelope calculations based on that factoid.”

He too questioned why obesity rates are rising in London given the TfL ban. “Nowhere in the study is the reality of what has actually happened in London since 2019, when the ban was introduced, allowed to intrude. Child obesity rates have risen across the UK since 2019, but the biggest increase has been in London. In England, obesity among 11 year olds rose from 21 per cent to 25.5 per cent, but rates shot up twice as fast in London, from 23.7 per cent to 30 per cent. London now has the highest rate of childhood obesity in the country.

“Since the pandemic, I suspect people have grown weary of politically motivated public health modelling that bears no relationship to reality. Taxpayers shouldn’t have to pay for this rubbish.”

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