Supermarket fruit and vegetable placement trial: outcomes in store sales, customer purchasing, diet and household waste in a prospective matched-controlled cluster study

BackgroundPrevious product placement trials have been underpowered and limited in outcomes. This study assessed effects of positioning an expanded fruit and vegetable section near entrances on store-level sales, household-level purchasing and waste, and dietary behaviours. MethodsThis prospective matched controlled cluster trial (NIHR 17/44/46) involved 36 stores (18 intervention and 18 control) of a discount supermarket chain in England. The intervention was implemented for six months. Control stores were matched on store sales, customer profiles and neighbourhood deprivation. Women customers aged 18 to 60 years, with loyalty cards, were assigned to the intervention (n=280) or control group (n=300). ResultsInterrupted time series analyses showed increases in store-level sales of fruit and vegetables were greater in intervention stores than predicted at intervention implementation (0.32SDs (95%CI 0.11, 0.53), p=0.002) and 3-months (0.23SDs (95%CI -0.05, 0.52), p=0.10) and 6-months follow-up (0.18SDs (-0.16, 0.52), p=0.29), equivalent to [~]2525 (95% CI 775, 4115), 1940 (95% CI 380, 3950) and 1450 (95% CI -945, 3950) extra portions per store, per week respectively. Effect sizes were somewhat stronger in stores where the produce section moved forward further. Proportion of households purchasing fruit and vegetables were somewhat protected among intervention compared to control participants. Changes in dietary quality were small but generally in the direction for health benefit. Change in frequency of household vegetable waste was negligible at 3-month follow-up but increased at 6-months. InterpretationPositioning produce sections near supermarket entrances can improve the nutrition profile of store sales and may improve household purchasing and dietary quality. Trial registrationNCT03573973. Research in ContextO_ST_ABSEvidence before this studyC_ST_ABSO_LIObesity and poor diet are major public health concerns and retailers marketing strategies impact food choices C_LIO_LIProduct placement is a marketing strategy used by many retailers to promote unhealthy foods C_LIO_LIGovernments are beginning to ban the placement of unhealthy foods at locations such as store entrances, checkouts and aisle ends in large retailers, in-store and online C_LI Added value of this studyO_LIResearch from adequately powered, robustly designed real-world studies on the prominent placement of healthy foods can inform improvements to existing regulations to maximise their impact on population diet C_LIO_LIPositioning an expanded fruit and vegetable section near store entrances increased fresh and vegetable sales at the population level; this intervention may protect against declines in household produce purchasing, particularly when exposed to a greater intervention dose C_LI Implications of all the available evidenceO_LIGovernment regulations to curb placement marketing strategies being used by retailers to promote unhealthy foods should consider requiring the placement of a fruit and vegetables section at store entrances alongside limiting placement of unhealthy foods in locations such as checkouts, aisle-ends and store entrances to maximise their health C_LI