Background Previous 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. Methods This 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). Results Interrupted 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. Interpretation Positioning produce sections near supermarket entrances can improve the nutrition profile of store sales and may improve household purchasing and dietary quality. Trial registration NCT03573973.

No funding was received from the supermarket involved in this study and all analyses were conducted independently, without involvement of supermarket staff. We, the authors, have read the journal?s policy and CV, SC, PD, JL, GM, WL, KB and JB have no conflicts of interest to declare. JC is Director of a spin out company Dietary Assessment Ltd. CC has has received consultancy, lecture fees and honoraria from AMGEN, GKS, Alliance for Better Bone Health, MSD, Eli Lilly, Pfizer, Novartis, Servier, Medtronic and Roche. The study described in this manuscript is not related to these conflicted relationships.

NCT03573973, pre-results

https://bmjopen.bmj.com/content/bmjopen/10/2/e036758.full.pdf

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It was approved by the University of Southampton, Faculty of Medicine Ethics Committee (ID 20986.A9) and conducted in accordance with the Declaration of Helsinki and Data Protection regulations.

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