The research, which was carried out in England by the University of Leeds, estimates that two million fewer HFSS products were sold per day since restrictions were introduced.
The legislation was put in place in October 2022 as part of the UK Government’s Childhood Obesity Strategy and limits the location of products high in fat, salt and sugar.
Prior to its rollout, 20 out of every 100 items sold were in-scope HFSS products – a number which has fallen to 19 since the legislation took effect.
How was the research conducted?
The researchers used store level sales and product data from Asda, Morrisons, Sainsbury’s and Tesco, alongside the Priority Places for Food Index – an online tool which identifies neighbourhoods most in need of support to access affordable, healthy and sustainable foods.
They also conducted surveys and interviews with representatives from the four UK supermarkets, the British Retail Consortium (BRC) and enforcement officers.
Nearly 2,000 shoppers were also surveyed to find out how the legislation was perceived and how it impacted shopping behaviours.
The size of this study is enormous. We analysed real-world data from 11.6 billion product sales, collected over 2.5 years from 480 stores across England, which is far bigger than traditional dietary studies that rely on self-reported surveys or receipts.
Dr Emma Wilkins, research fellow in Nutrition and Lifestyle Analytics at the University of Leeds
How do retailers feel about HFSS?
Despite some implementation challenges, the retailers surveyed said they felt the legislation was a positive step and supported the fundamental aim to reduce obesity.
Whilst the legislation does not cover Scotland and Wales, the research on sales from a smaller number of stores in these nations revealed that aspects of the rules may have carried across.
The researchers surmised this could be because some retailers decided to implement the legislation across all their stores, or it may be a result of the considerable reformulation work across industry, with three out of four retailers saying the legislation led to a change in their reformulation plans.
If products were reformulated, to comply with the legislation, this would have been carried across national borders, as many of the same products are sold in stores across the devolved nations.
How do consumers feel about HFSS?
Most shoppers said they felt the rules have been a good step in encouraging healthier food choices; although 73% didn’t think it would impact their own shopping behaviour. A similar number (71%) believe it would have more impact on others who do not plan their shopping.
The majority of shoppers (90%) said they believe making healthier foods affordable is just as, if not more, important than the legislation against less healthy food.
The legislation was intended to go unnoticed and that was largely achieved, as 56% of shoppers did not notice any changes in store. Shoppers also reported that they still found it ‘easy’ or ‘very easy’ to find the HFSS food and drinks in the supermarket.
HFSS regulation is effective
Professor Michelle Morris, who led the team responsible for analysing the data at the University of Leeds, said the research shows the legislation has been “a force for good”.
She added: “But more now needs to be done to make healthy and sustainable diets the easy choice for our population, so that we can shift more people’s eating habits towards the national recommendations of the Eatwell Guide.”
Dr Alison Fildes from the University of Leeds School of Psychology, was a co-investigator on the project. Commenting on the results, she said: “Our findings suggested shoppers were in favour of the HFSS legislation. However, they also expressed their support for greater promotion and affordability of healthy foods.
“Tightening the current legislating to ensure HFSS products are replaced in prominent locations with healthier foods, would go further towards helping shoppers make healthier purchases.”
The research is part of a broader UK Research and Innovation Transforming UK Food Systems-funded academic collaboration called, Diet and Health Inequalities (DIO-Food). This is led by Professor Alexandra Johnstone at the Rowett Institute, University of Aberdeen.
Johnstone said: “It is critical that any new legislation does not widen dietary inequalities for vulnerable groups, like people living with food insecurity.
“We are reassured to see from our research that the impact of the HFSS legislation was equitable in stores located in areas with different levels of priority according to the Priority Places for Food Index.”
The positive results of this study come just one month after the UK Government revealed its intentions to repeal upcoming volume price promotions and aisle placement rules related to HFSS products in favour of a new strategy called ‘Smarter Regulation’.
The plan also includes an update to how foods are measured and identified as healthy, with Labour describing the 2004 NPM as dated.