Real-life effects of nudging and pricing strategies in the supermarket to promote healthy diets

Abstract Background Unhealthy dietary patterns pose a major public health challenge. Individual-level efforts to promote heathy diets (e.g. nutrition education) have limited effect on the long term. Context-specific interventions focussing on point-of-purchase may create opportunities for sustainable dietary changes. We evaluated real-life effects of nudging and pricing strategies in supermarkets on dietary intake. Methods In this parallel cluster-randomised controlled trial, we randomized 12 Dutch supermarkets in socially deprived neighbourhoods to a control group (n = 6), or intervention group (n = 6). Healthy food nudges were implemented in intervention stores across 13 food groups, combined with healthy product price decreases and unhealthy product price increases. Eligible participants were aged 30-80 years and regular shoppers at participating stores. The primary outcome was dietary guideline adherence measured via an index score (0-150), at baseline and after 3, 6 and 12 months. Secondary outcomes included parameters of cardiometabolic health (HbA1c, lipid profile, and waist circumference), the percentage of healthy food purchases in the supermarket, socio-cognitive factors, and supermarket customer satisfaction. Effects were analysed with linear mixed models. Results This study included 173 participants from intervention clusters and 220 from control clusters. Preliminary evaluation of the 3-month follow-up data revealed no effectiveness of the nudging and pricing strategies compared to the control supermarkets in terms of dietary guideline adherence (β -0.8, 95%CI -4.2; 2.7). Results on all outcomes will be available at time of the conference. Conclusions This novel supermarket trial is the first to evaluate real-life long-term effects of nudging and pricing strategies based on a comprehensive set of study outcomes and using a strong methodological design. Findings can direct future design of context-specific interventions focussing on the promotion of healthy diets. Key messages • Context-specific interventions focussing on point-of-purchase may create opportunities for sustainable dietary changes. • Findings from this supermarket trial testing real-life and long-term effects of nudging and pricing strategies can direct future design of context-specific interventions focussing on healthy diets.


Background:
Unhealthy dietary patterns pose a major public health challenge.Individual-level efforts to promote heathy diets (e.g.nutrition education) have limited effect on the long term.Context-specific interventions focussing on point-of-purchase may create opportunities for sustainable dietary changes.We evaluated real-life effects of nudging and pricing strategies in supermarkets on dietary intake.

Methods:
In this parallel cluster-randomised controlled trial, we randomized 12 Dutch supermarkets in socially deprived neighbourhoods to a control group (n = 6), or intervention group (n = 6).Healthy food nudges were implemented in intervention stores across 13 food groups, combined with healthy product price decreases and unhealthy product price increases.Eligible participants were aged 30-80 years and regular shoppers at participating stores.The primary outcome was dietary guideline adherence measured via an index score (0-150), at baseline and after 3, 6 and 12 months.Secondary outcomes included parameters of cardiometabolic health (HbA1c, lipid profile, and waist circumference), the percentage of healthy food purchases in the supermarket, socio-cognitive factors, and supermarket customer satisfaction.Effects were analysed with linear mixed models.

Results:
This study included 173 participants from intervention clusters and 220 from control clusters.Preliminary evaluation of the 3month follow-up data revealed no effectiveness of the nudging and pricing strategies compared to the control supermarkets in terms of dietary guideline adherence (b -0.8, 95%CI -4.2; 2.7).Results on all outcomes will be available at time of the conference.

Conclusions:
This novel supermarket trial is the first to evaluate real-life long-term effects of nudging and pricing strategies based on a comprehensive set of study outcomes and using a strong methodological design.Findings can direct future design of context-specific interventions focussing on the promotion of healthy diets.

Key messages:
Context Meal timings and daily night-time fasting periods can synchronise the circadian system, which regulates the cardiovascular system.The present study aims to evaluate the prospective associations between circadian nutritional behaviours, defined by meal timing and frequency, and the risk of cardiovascular diseases.We used data from 103,389 adults (79% females) in the French NutriNet-Sante ´study, 2009-2021.Circadian nutritional behaviours were assessed using repeated 24h food records during the first two years of follow-up.We examined the associations between circadian eating behaviours and risk of cardiovascular, coronary heart and cerebrovascular diseases by multivariable Cox proportional hazard models.During a median follow-up of 7.2 years, 2036 incident cardiovascular diseases were diagnosed.A later first meal of the day was associated with a higher risk of cardiovascular diseases (HR per hour increase = 1.06, 95% CI 1.01 -1.12).A later last meal of the day was associated with a higher risk of cerebrovascular diseases (HR per hour increase = 1.08, 95% CI 1.01 -1.15).Among women, a later last meal was also associated with a higher risk of cardiovascular disease (HR per hour increase = 1.08, 95% CI 1.01 -1.15).We found no evidence for an association between night-time fasting duration nor meal frequency, with risk of cardiovascular diseases.This study suggests that the habit of eating a later first meal, and a later last meal (in women) could be associated with a higher risk of developing circulatory diseases.These results need to be confirmed in other largescale studies before they can be transferable to clinical practice.

Key messages:
Beyond nutritional quality of meals, meal timing could also be a risk factor for cardiovascular disease.If confirmed in other largescale studies, early breakfast and dinner could be considered in preventive strategies of cardiovascular diseases.
Abstract citation ID: ckac129.552 The Southern European Atlantic Diet and depression incidence: a multicohort study

Adria ´n Carballo-Casla
A Carballo-Casla 1,2 , D Stefler 3 , R Ortola ´1,2 , Y Chen 3 , R Kubinova 4 , A Pajak 5 , S Malyutina 7 , F Rodrı ´guez-Artalejo -specific interventions focussing on point-of-purchase may create opportunities for sustainable dietary changes.Findings from this supermarket trial testing real-life and long-term effects of nudging and pricing strategies can direct future design of context-specific interventions focussing on healthy diets.