Title: Nudging healthier dietary habits: evaluation of a supermarket placement strategy in the WRAPPED study
Funder: Department of Health and Social Care

Abstract: As many as 42,000 deaths could be prevented each year if people in the UK ate more fruit and vegetables. The diets of women are important for their own health and for the short- and long-term health of their families. Supermarkets are a major source of food for families, but poor placement of healthy foods in supermarkets could be a barrier to eating well. Little research has been done to answer the question: ‘Does placing fruit and vegetables at the store entrance influence what people buy and eat?’ This study provides a unique opportunity to answer this question. Discount supermarkets have less healthy environments than other types of supermarkets and are used frequently by disadvantaged families. _x000D_ _x000D_ A UK discount supermarket chain is changing the layout in its stores to improve the availability and positioning of fresh fruit and vegetables. We have already seen, in a pilot study of six stores that changing the placement of products in stores seems to improve women’s diets. Now we need to find out whether these findings are also true in a large study. This study (WRAPPED - Women’s Responses to Adjusted Product Placement and its Effects on Diet) will recruit 432 women aged 18-60 years who regularly shop at one of 48 stores across England to participate (9 women from each store). 216 women will shop at 24 stores changing their layout and 216 women at 24 similar stores where the layout will not change. We will survey the women four times (once before the change in layout and one, three and six months after). Women will receive up to £30 of Love2Shop vouchers as incentives to participate. The survey will ask about the fruit and vegetables and other foods they, and their young children (2-6 years) usually eat, where they shop for grocery food, their views on the supermarket environment and beliefs about healthy eating. We will ask them about their age, number of children, highest educational qualification and how much they usually spend on grocery food each week. Information about each woman’s food purchasing patterns and the total sales of fruit and vegetables for each store in the study will be obtained from the supermarket._x000D_ _x000D_ The results will tell us whether having a greater range and prominent positioning of fruit and vegetables improves women's fresh fruit and vegetable purchasing and their own and young children’s diets. All information shared by the women and the supermarket chain will be kept strictly confidential and only with participant’s consent. The research team are conducting the study and will analyse the results independently of company, and have not taken any money from the company to support the research. We will invite two women who shop regularly at this supermarket to become part of the research team. They will help to make the surveys and other materials easy to read and understand, find the best ways to keep women engaged in the study and help us think about the results from their perspective as regular supermarket shoppers. We will give them Love2shop vouchers to thank them for their time. Study findings will be of interest to the public, researchers, food retailers and the government. The results could be used by the government or supermarkets to create in-store layouts that prompt customers to buy healthy foods. Healthier layouts across all supermarkets could help everyone to eat better, not just those who are interested in eating healthy foods, helping people to have a healthy weight and be less likely to develop diabetes or heart disease.

Lay abstract: Background: Unhealthy diet is a key modifiable risk factor for obesity and non-communicable diseases (NCDs). The cost of poor diet-related ill health to the NHS is £5.8 billion annually. Supermarkets account for 87% of UK grocery sales. UK government policy supports altering such environments to ‘nudge’ people into making healthier choices. High quality empirical evidence that ‘nudge’ placement initiatives are effective is needed. Testing environmental strategies that help families, particularly those from disadvantaged backgrounds, to make healthy food choices is necessary to reduce obesity prevalence and improve population health. _x000D_ _x000D_ Aim: This study is the largest supermarket trial internationally and will assess the effectiveness and cost-effectiveness of improving the placement of fresh fruit and vegetables in supermarkets in improving the fresh fruit and vegetable purchasing of women aged 18-60 years._x000D_ _x000D_ Plan of Investigation: WRAPPED (Women’s Responses to Adjusted Product Placement and its Effects on Diet) is a natural experiment with a prospective matched controlled cluster design. The setting is a UK discount supermarket chain regularly used by many disadvantaged families for their main shop. The intervention involves creation of a new, expanded fresh fruit and vegetable section near the store entrance. Control stores keep the existing layout with a limited range of fresh fruit and vegetables and placement of fresh fruit and vegetables at the back of the store. A pilot phase demonstrated improved diet quality amongst women shopping in intervention stores when compared with those shopping in control stores. An appropriately powered study is required. _x000D_ _x000D_ We will recruit 9 participants from each of 24 intervention and 24 matched control stores through the retailer’s loyalty card scheme (postal letter) and shop floor recruitment, and provide incentives of up to £30 Love2Shop or Amazon vouchers; these methods proved effective during the pilot. Participants will be women aged 18-60 years who shopped at a study store in the 12 weeks before recruitment. This study is unique in its collection of individual level sales data, as well as demographic and dietary information, and is the first to collect outcome data for more than one family member. Participant’s weekly sales data will be obtained through the retailer’s loyalty card scheme and will cover 3 months before refurbishment, plus 0-6 months post intervention. Change in women’s fresh fruit and vegetable purchasing from baseline to 6 months is the primary outcome. Secondary outcome data about women's diets, their young child's diet (2-6 years), food shopping habits, perceptions of supermarket environment, and psychosocial and demographic characteristics will be collected by telephone survey before refurbishment, and 1, 3 and 6 months after. Weekly sales data for study stores will be provided by the retailer. Cost-effectiveness will be assessed from individual, retailer and societal perspectives. Process evaluation will assess intervention implementation, mechanisms of impact and context._x000D_ _x000D_ Public health benefits: Our study is politically and scientifically important being one of the first field studies of this kind. The findings could provide strong evidence for future public health policy interventions to help address inequalities in diet and NCD risk by supporting development of a healthy store layout that could be adopted more widely in food retail outlets.

Research activity codes: 3.2 INTERVENTIONS TO ALTER PHYSICAL AND BIOLOGICAL ENVIRONMENTAL RISKS
Health categories: CANCER AND NEOPLASMS;CARDIOVASCULAR;METABOLIC AND ENDOCRINE;ORAL AND GASTROINTESTINAL;STROKE