HFSS legislation: Independent evaluation summary
22 August 2025England’s HFSS placement legislation had a significant impact. Learn how the University of Leeds, IGD and major retailers worked in collaboration.
The first independent evaluation of the HFSS (high in fat, sugar, or salt) legislation, introduced in England in October 2022 as part of the UK Government's Childhood Obesity Strategy, has been completed.
The University of Leeds, IGD and four major retailers worked in collaboration to share data to enable an independent analysis by the University of Leeds to understand the impact of the HFSS legislation. This level of collaborative research and data sharing had not previously been undertaken within the food industry, making the research the first of its kind.
The research estimates a 0.63% point reduction in sales of in-scope HFSS products as a proportion of total sales by weight, followed the introduction of the legislation. This equates to two million fewer in-scope HFSS products sold per day after the new legislation took effect. It found that before the legislation was implemented, 20 out of every 100 items sold were in-scope HFSS products. Following legislation this number dropped to 19.
How was the research undertaken?
The University of Leeds, IGD and four major retailers, including ASDA, Morrisons, Tesco and Sainsburys, worked in collaboration over a two-year period to share data. This enabled an independent analysis by researchers at the University of Leeds to understand the impact of the HFSS legislation. This research is part of a broader UKRI Transforming UK Food Systems academic collaboration, led by Professor Alex Johnstone at the Rowett Institute, University of Aberdeen on the Diet and Health Inequalities (DIO food) project.
For the evaluation, researchers used store level sales and product data from Asda, Morrisons, Sainsbury’s and Tesco, alongside the Priority Places for Food Index1, an online tool which identifies neighbourhoods most in need of support to access affordable, healthy and sustainable foods.
They conducted surveys and interviews with representatives from the four UK supermarkets, the British Retail Consortium (BRC) and enforcement officers.
Nearly 2,000 shoppers were surveyed to find out how the legislation was perceived and how it impacted shopping behaviours.
Data were analysed by researchers in the Nutrition and Lifestyle Analytics team at the University of Leeds, led by Professor Michelle Morris.
“Our research shows that the HFSS legislation was a force for good, leading to significant reduction in sales of in-scope HFSS products. 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.”
— Professor Michelle Morris, University of Leeds
Research findings
The legislation reduced sales of HFSS products as a proportion of total sales
The combined results from three retailers2 show a statistically significant reduction in the sales of in-scope HFSS products, as a proportion of total sales by weight and by unit volume, in stores in England, following the introduction of the legislation.
For the fourth retailer, it was not possible to overcome data preparation challenges (linking sales records to nutrition metrics) within the project time period,
A “step change” was observed after the legislation was introduced. Whilst pre and post-legislation trends of in-scope HFSS sales were similar, post-legislation this trend was at a lower level. The researchers believe this may dispel any arguments that the changes were driven by the cost of living. If it were driven by inflation, there would be a gradual change throughout the data collection period, in line with the Consumer Price Index.
The scale of the impact varied by retailer, with two retailers’ sales showing a clear step change reduction in sales of in-scope HFSS products. No significant impact was observed in the third.
Where there was an impact seen in the retailers, it was equitable across different geographical areas
By using stores across each decile of the Priority Places for Food Index (PPFI) areas, the researchers were able to identify how shops in different types of neighbourhoods have been affected by the legislation.
The impact of the legislation on sales of in-scope HFSS products was consistent in supermarkets across all deciles of the Priority Places for Food Index, indicating that the legislation was equitable.
Retailers made a variety of changes in-store in response to the legislation
Whilst the legislation restricted in-scope HFSS products from being placed in certain prominent locations, there was no guidance on what should be placed there instead. This meant that lots of different changes were made in store across retailers, and interviews with retailers demonstrated that they implemented different strategies.
For end of aisle space, retailers implemented a mix of strategies including placing non-HFSS (healthier or non-food) products there as intended, while others used the space for exempt products such as baby food, out-of-scope HFSS products or alcohol, and in some stores, digital advertising replaced HFSS products.
As for store layout, areas that were not subject to the restrictions were utilised for in-scope HFSS products instead. For example, aisles were lengthened and free-standing display units introduced to promote products. Food-to-go sections were moved to the back of the store so that they could continue to be displayed as one unit but not in a prime space. Seasonal lines were moved into one aisle rather than at front of store on pallets.
Despite some implementation challenges, the retailers interviewed felt the legislation was a positive step and supported the fundamental aim to reduce obesity.
The legislation did not cover Scotland and Wales. However, the research on sales from a smaller number of stores in these nations found aspects may have carried across. This could be because some retailers decided to implement the legislation across all their stores throughout England, Scotland and Wales. Even for those that didn’t choose to do this, it may have been difficult to implement different policies across different areas, leading to some duplication of store set ups, even if not intended.
There was also considerable reformulation by industry (lowering fat, salt or sugar from products or adding fruit, vegetables, nuts, protein and fibre), with three out of four retailers saying the legislation changed 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 England, Scotland and Wales.
Shoppers surveyed said the legislation was a good first step
Most shoppers felt it was a good step to encourage healthier food choices. Although 73% of shoppers didn’t think it would impact their own shopping behaviour, a similar number (71%) believed it would have more impact on others who did not plan their shopping. Nearly all shoppers surveyed (90%) thought making healthier foods affordable was 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. They still found it easy or very easy to find the HFSS food and drinks in the supermarket.
Whether they noticed it or not, the results show that fewer HFSS products, as a proportion of total purchases, were bought following the legislation, suggesting it affected consumer behaviour. The research estimates that two million fewer in-scope HFSS products were sold per day after the new law took effect. Before the legislation was implemented, 20 out of every 100 items sold were in-scope HFSS products. Following legislation this dropped to 19.
In summary
“This independent evaluation of HFSS placement regulation is an important piece of work to better understand the impact that Government policy has on behaviour change. Over a three-year period, we connected industry, academia and government, helping translate academic research into industry relevant resources that drive action. This marks the first independent evaluation of HFSS legislation. It demonstrates that the legislation has a significant impact on sales. Beyond sales, we know industry reformulated and innovated at scale to make their products non-HFSS. Whilst this research was unable to capture the impact of reformulation alongside sales, we know that these cumulative, small sustainable behaviour changes for customers can lead to significant impacts over time.”
— Kirsty Saddler, Director of Health and Sustainability at IGD
IGD Evaluation of the HFSS placement legislation report
The Retailer Survey and Interview paper
This research was funded through the Transforming the UK Food System for Healthy People and a Healthy Environment SPF Programme, delivered by UKRI, in partnership with the Global Food Security Programme, BBSRC, ESRC, MRC, NERC, Defra, DHSC, OHID, Innovate UK and FSA. IGD provided additional support through their Social Impact programmes on healthy and sustainable diets. IGD further supported by convening retailers and disseminating findings.