Junk food ad restrictions linked to reducing high fat, salt & sugar purchases

A ban on outdoor advertising of junk food shown to have success in London could also be used to tackle diet-related-diseases in the North East, says co-author of a new study evaluating the policy from Fuse and Teesside University.

The restrictions on the 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, according to the new research in PLOS Medicine.

The study co-authored by Fuse Associate Director Professor Amelia Lake from Teesside University and funded by the NIHR School for Public Health Research (SPHR), used data from two million grocery purchases of high fat, salt and sugar food products to examine the effect of the policy.

It found households purchased 1,000 less calories from HFSS products per week, a reduction of 6.7 per cent. Chocolate and confectionery saw the sharpest decrease with weekly purchases falling by 318 calories, a 20 per cent reduction. Overall, Londoners were on average buying the equivalent of just under one and a half milk chocolate bars less per week.

The Government’s Sugary Drinks Industry Levy (SDIL), which was widely considered a success, showed a reduction in sugar purchases of 32g per week. In this latest study, the advertising restrictions are shown to have had more than double the impact, with a reduction on sugar purchases of 80.7g per week.

“In the North East, given the wide health inequalities, this is an effective means by which local authorities can look at their stations, their bus shelters and their wider outdoor advertising and take steps similar to Transport for London.”

Professor Amelia Lake, Fuse Associate Director

Prof Amelia Lake, dietitian and Professor of Public Health Nutrition, said: “Wide reaching policies like these do work.

“This restriction of the advertisement of products with high fat, salt, and sugar content changed what people consumed and the effect size was even bigger than that of the sugar levy.

“This is an important finding which can be used by local authorities and by other governments wanting to tackle diet-related-diseases.

“In the North East, given the wide health inequalities, this is an effective means by which local authorities can look at their stations, their bus shelters and their wider outdoor advertising and take steps similar to Transport for London.”

In November 2018, restrictions on the outdoor advertising of HFSS foods and drinks across the London Underground, the TfL Rail network, and at bus stops were announced by Mayor of London Sadiq Khan and were fully implemented on 25 February 2019.

Using data collected by Kantar, a commercial consumer data company, the research team looked at a sample of household food and drink purchases in London and the North of England - where purchasing trends are similar to London but restrictions were not implemented - and conducted a wide range of tests to assess other factors which may have had a bearing on food purchases. When all this was taken into account there was strong evidence that the changes in household purchases in London were a result of the policy.

The study ran from 18 June 2018 to 29 December 2019 and compared average weekly purchases of HFSS products in 977 London households to an estimate of what would have happened without the policy.

The restrictions cover all adverts for food and non-alcoholic drinks high in fat, or sugar and considered “less healthy” under Public Health England (now the Office for Health Improvement and Disparities) guidelines. Examples of products that would likely not be accepted include sugary drinks, cheeseburgers, chocolate bars and salted nuts, while unsalted nuts, raisins and sugar free drinks would likely be accepted. Food and drink brands, restaurants, takeaways and delivery services are only able to place adverts which promote their healthier products, rather than simply publicising brands.

London has one of the highest child overweight and obesity rates in Europe, with nearly a third (30 per cent) of the capital's children aged 10 and 11 overweight or obese. Children living in the most deprived areas are disproportionately affected and are more than twice as likely to be obese than those living in the least deprived areas. A 2021 BMJ Open study revealed that adults in lower socioeconomic groups and young adults are more likely be exposed to HFSS advertising.

Lead author Dr Amy Yau, from the London School of Hygiene & Tropical Medicine (LSHTM), said: “Many governments and local authorities are considering advertising restrictions to reduce consumption of high fat, salt and sugar 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 team say that while the results are encouraging, the intervention was effective in reducing growth of high fat, salt and sugar purchases rather than achieving absolute reductions in HFSS purchases.

The Mayor of London, Sadiq Khan, said: “There is no denying that advertising plays an enormous role in putting less healthy food and drink in the spotlight, and I am pleased to see the positive impact these ground-breaking measures have had, leading to a real reduction in the amount of junk food being purchased.”

The authors acknowledge 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.

The study was conducted in collaboration with the University of Cambridge, University of Hertfordshire, University of Liverpool, University of Bristol and Fuse, the Centre for Translational Research in Public Health.

The research was an independent evaluation funded by NIHR School for Public Health Research (SPHR) Grant Reference Number PD-SPH-2015.


Aadapted from a press release issued by LSHTM.

Image: Photograph 'Junk food decisions' by Richard Rutter via Flickr © 2008: (CC BY-SA 2.0)

Last modified: Thu, 17 Feb 2022 20:07:37 GMT