Chubby checker: Industry chews out TfL HFSS ad claims

The advertising and marketing industry has hit back at claims that Transport for London’s junk food ad ban has saved the NHS hundreds of millions and prevented tens of thousands of obesity cases in the capital, branding them “over-optimistic”.

The ban, implemented in February 2019, means food and drink brands, restaurants, takeaways and delivery services are only able to place ads which promote their healthier products.

The research, published earlier this week by the London School of Hygiene & Tropical Medicine (LSHTM) in the International Journal of Behavioural Nutrition & Physical Activity, claims the move has prevented almost 100,000 obesity cases in the UK and is expected to save the NHS over £200m over the lifetime of the current population.

Researchers compared almost 2 million weekly grocery purchases of products high in fat, salt, and sugar (HFSS) by households in London and the North of England between June 2018 and December 2019.

They maintain that the policy contributed to a 1,000 calorie decrease in energy from unhealthy food purchases in consumers’ weekly shopping, compared to what would have happened without it.

However, according to the Advertising Association and ISBA, leading economic consultancy SLG Economics claims the results of LSHTM research “fail an important statistical test” that reduces their validity and “the robustness of the conclusions”.

And SLG Economics is no fly-by-night operation. The economics consultancy was set up in 2011 by Stephen Gibson, providing specialist micro-economic policy advice to regulated companies, regulators and the UK Government.

Gibson has over 25 years’ experience as a professional applied economist, the past 15 of which have focused on public policy decision making; he is also chair of the Government’s Regulatory Policy Committee, which is the independent expert body responsible for scrutinising and assessing the quality of government departments’ and regulators’ impact assessments.

Among the raft of findings from SLG Economics are that the LSHTM study misses out over half (by calories purchased) of the HFSS product groups and as a result does not explain where 57% of the reported reduction in calories comes from.

SLG also suggests the results are 32 to 109 times higher than the expected results from a 9pm watershed ban on HFSS ads on TV, a fact SLG insists “is not a credible result”.

In addition, the LSHTM study excludes out-of-home purchases, where one might expect TfL ads to have a much greater impact, again questioning the credibility of the results.

Meanwhile, SLG points to evidence from the National Child Measurement Programme that the prevalence of overweight and obese children increased in London faster than in any of the TfL control group areas in the North of England – once again contradicting the LSHTM study results.

Finally, SLG argues that it is a serious methodological gap to not take into account the extent to which people in the survey would have had the opportunity to see HFSS ads on the TfL estate and how that would have changed over the period of the study.

SLG concludes: “The results fail an important statistical test which reduces the statistical validity of the results and the robustness of the conclusions.”

Advertising Association chief executive Stephen Woodford commented: “Tackling obesity is a critical issue and it is important that any policy interventions are evidence-based and deliver value for money.

“The modelling in the latest research study claims that the Mayor’s junk food ad ban on the TfL estate will save the NHS £218m over the lifetime of the current population, and result in nearly 95,000 fewer cases of obesity.

“We find these results surprising and over-optimistic, especially as childhood obesity continues to rise in the capital and given that the Government’s own estimate of an HFSS online ban and TV advertising watershed restriction is that it would only reduce calorie intake by 2-3 calories a day.

“We believe tackling obesity through levelling up and dealing with the cost of living crisis would be far more effective in decreasing obesity rates not only among children, but through the whole of the UK population.”