The Government in England has proposed legislation to restrict promotions of less healthy items in prominent locations in stores to help reduce over-consumption. In the study, shoppers in the intervention stores purchased fewer calories overall compared to control stores, suggesting that this policy could make an important contribution to efforts to prevent obesity.
A second paper by the same group evaluates six interventions within major UK grocery stores to encourage selection of healthier foods, including availability, positioning, promotions and signage strategies to encourage selection of healthier products.
Increasing the availability of healthy items, or using price promotions, showed some promise, but there was no evidence that altering the position on shelves, or adding shelf-edge labels to advertise healthier foods is associated with changes in purchasing behaviours. Both papers are published in PLOS Medicine.
Dr Carmen Piernas, of the Nuffield Department of Primary Care Health Sciences at the University of Oxford says: “Obesity is a global public health issue, and diets in the UK do not meet recommendations for saturated fat, fibre, sugars and salt. Public health campaigns have had only limited success, and calls for interventions such as taxes on less healthy foods have met with considerable opposition. We were keen to look for ways that might nudge people to make healthier food choices while shopping for food.”
Piernas and colleagues partnered with a large UK food retailer to reduce the extra availability of seasonal chocolate by removing freestanding promotional displays and substituting it with other products on the end of aisles. All the products were still available for purchase elsewhere in the store. The intervention took place for seven weeks before Easter 2019.
In the run up to Easter, stores usually experience an increase in sales of Easter eggs and other seasonal confectionery. The increase in control stores compared to the previous year was 18%. However, in the intervention stores, the team saw an increase of only 5% compared to Easter 2018. There was an absolute difference between intervention and control stores of approximately 127 units or around ~21 kg of confectionery per store per week.
The investigators reported significant reductions in total energy from all food-related purchases in the stores implementing the intervention. There was also a decline in total fat but although saturated fat and sugar did reduce a little, this was not significant. There was no evidence that the main results varied according to the level of deprivation in the local neighbourhood.
Working with three large UK supermarkets, the same group evaluated a range of approaches that might encourage an increase in healthy purchases. Again, they compared intervention and control stores and tested availability, positioning, promotions and signage strategies to encourage selection of healthier products.
Expanding the availability of healthier options within a category, for example placing lower fat frozen chips or lower energy biscuit packs next to standard chips and biscuits was associated with significant increases in purchases of the healthier items and a corresponding decline in the less healthier options. Promotions led to a significant initial uplift in sales of the healthier target products but these changes declined over time.
The researchers found no evidence of changes in purchasing behaviours from altering the positioning of healthier cereals within an aisle or shelf-edge labelling or highlighting the availability of lower or non-sugar drinks.
Dr Piernas says: “Forthcoming legislation in England will restrict promotions on foods high in fat, sugar and salt in prominent locations in stores, and our research provides important evidence that suggests this could be an effective strategy to reduce over-consumption.”
Removing seasonal confectionery from prominent store locations and purchasing behaviour within a major UK supermarket: Evaluation of a nonrandomised controlled intervention study. Piernas C, Harmer G, Jebb SA will be published in PLoS Medicine on Thursday 24 March, 2022 http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1003951