Positive impact of supermarket junk food restrictions revealed

Legislation to restrict supermarket sales of foods high in fat, sugar or salt (HFSS) has led to a marked reduction in purchases, according to the first ever independent analysis.

The research, which was carried out in England by the University of Leeds, 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 number dropped to 19.

Our research shows that the HFSS legislation was a force for good but more now needs to be done to make healthy and sustainable diets the easy choice for our population.

Professor Michelle Morris, School of Food Science and Nutrition.

For the evaluation, 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 legislation, which restricts the location of products that are high in fat, sugar or salt (HFSS), was introduced in England in October 2022 as part of the UK Government's Childhood Obesity Strategy.

Data were analysed by researchers in the Nutrition and Lifestyle Analytics team at the University of Leeds, led by Professor Michelle Morris. She said: “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.”

The research is part of a broader UK Research and Innovation Transforming UK Food Systems-funded academic collaboration entitled Diet and Health Inequalities (DIO-Food), which is led by Professor Alexandra Johnstone at the Rowett Institute, University of Aberdeen. She 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.”

Dr Alison Fildes, of the University of Leeds School of Psychology, was a co-investigator on the project. She added: “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”

Research findings

The legislation reduced sales of HFSS products as a proportion of total sales:

The combined results from three retailers 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.

Research recommendations

Eight recommendations are being made to policymakers as a result of the research findings:

Strengthen legislation to mandate against promotion of less healthy foods
Ensure healthier foods are more affordable
Make available an open, regularly updated food composition database for HFSS classification of food and drinks
Allocate sufficient funding to allow evidence generation and robust and timely evaluation of legislation
Consult with context-specific experts to develop implementation guidance for food policy in complex retail environments
Ensure legislation is enforceable
Align government departments in their approach to food
Establish dedicated support and guidance to facilitate effective implementation of legislation.