PHOTO: Peter Bond/Unsplash
PHOTO: Peter Bond/Unsplash

Can supermarkets nudge people into buying healthier food?

Embargoed until: Publicly released:
Peer-reviewed: This work was reviewed and scrutinised by relevant independent experts.

Observational study: A study in which the subject is observed to see if there is a relationship between two or more things (eg: the consumption of diet drinks and obesity). Observational studies cannot prove that one thing causes another, only that they are linked.

People: This is a study based on research using people.

Limiting supermarket placement of seasonal sweets and increasing the availability of healthier alternatives in these stores may be promising interventions to encourage healthier purchases, according to two studies by a UK research team. In one study, researchers looked at grocery stores that removed free-standing promotional displays of Easter sweets in the seven weeks leading up to Easter, and kept the sweets available elsewhere in the store. The stores that retained the displays had an 18 per cent seasonal increase in sales of these treats, while the display-free stores only had a five per cent bump, translating to a difference of 21 kilos of Easter sweets per week. In the second study, the team evaluated six interventions to promote healthier products in three major UK grocery store chains, finding some interventions were linked to short-term changes in the healthier direction.

Journal/conference: PLOS Medicine

Link to research (DOI): 10.1371/journal.pmed.1003951

Organisation/s: University of Oxford, UK

Funder: See paper PDFs for full list of funders.

Media release

From: PLOS

Can supermarkets coax people into buying healthier food?

Restricting supermarket placement of less healthy items and increasing the availability of healthier alternatives in these stores may be promising interventions to encourage healthier purchasing behaviors. Those are the conclusions of two new studies publishing March 24th in PLOS Medicine by Carmen Piernas and colleagues of University of Oxford, UK.

Dietary targets for saturated fat, dietary fiber, sugar, and salt intake are currently not being met in the UK. Poor diets are an important risk factor for chronic diseases, and many socioeconomic inequalities remain when it comes to diet. Evidence from systematic reviews has suggested that grocery store interventions may be effective at changing diet, but evidence in real supermarkets has been lacking.

In the first new study, the researchers evaluated six interventions involving the availability, placement, promotions, and signage of healthier products within three major chains of UK grocery stores. They found that increasing the availability of healthier options within a category was associated with significant changes in purchasing. For instance, stocking low-fat chips next to regular chips decreased the sales of regular chips (-23% in intervention stores vs. -4% in control stores, p=0.001). Stocking more lower calorie biscuits increased sales by 18% and decreased purchases of regular, higher calorie biscuits by 4%.

In the second study, Piernas and colleagues evaluated a grocery store intervention to remove seasonal chocolates and candy from prominent locations within a major UK supermarket in the 7 weeks leading up to Easter. In 34 intervention stores, free-standing promotional displays of seasonal chocolate confectionery products were removed, although the candies were available elsewhere in the store. The researchers found an attenuation in the usual seasonal increase in confectionery sales; units of confectionery sales increased by 18% in the control stores during the pre-Easter period but only 5% in the intervention stores (p<0.001). The absolute difference in confectionery sales between control and intervention stores was approximately 21 kilograms per store per week, which translated in fewer total calories in customers' baskets.

Together, the papers offer new evidence on how legislation can help shape consumers’ diets with the goal of improving health. “This research has important implications for the development of policies by retailers or governments to bring dietary intakes closer to recommendations for good health,” the authors write. “Strategies aiming at informing customers about healthier options are unlikely to work in isolation.”

Regarding the first study, Piernas adds, “The Government in England has announced new legislation to restrict promotions of foods high in sugars, salt and saturated fat (HFSS) in prominent locations. This project established a partnership with a large UK food retailer to evaluate an intervention to remove seasonal chocolate confectionery from prominent areas of the store, specifically end-of-aisles and entrance areas, over 7 weeks before the Easter period. These results from a ‘real world’ intervention provide promising evidence that the proposed legislation in England to restrict promotions of less healthy items in prominent locations may help reduce over-consumption.”

Regarding the second study, Piernas adds, “In this multi-retailer partnership, we conducted an independent evaluation of six in-store interventions within three major UK food retailers aimed at improving food purchasing behaviours. We reported that some choice architecture interventions implemented within stores, such as availability and promotions, were associated with short-term changes in food purchasing behaviours. However, the effect of promotions on consumer behaviour may diminish with time and are less likely to be sustainable for retailers over longer time periods.”

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  • PLOS
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    URL after publication. This is for the paper on promoting Easter sweets.
  • PLOS
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    URL after publication. This is for the paper on supermarket interventions.

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