Taxation Online Experimental Supermarket

NCT07593937 | Not Yet Recruiting

• 1 other identifier: INSERM 25-1264
• Study Type: interventional
• Target: 2,239
• Locations: 1 country
• Sites: 1

Brief Summary

Scientific context The increase in the consumption of unhealthy food coupled with a suboptimal consumption of healthier options have increased the risk of non-communicable diseases (NCD) worldwide. Among other public policies to address the rise in NCD -such as front of pack labelling, regulation of food and beverages in schools, marketing regulations targeted to children- taxation has been recognized as a cost-effective strategy to reduce consumption of taxed products. Although subsidies have been used to reduce food insecurity, with the rise in NCD associated with unhealthy diets, studies have explored the feasibility of combining subsidies to incentivize the consumption healthy food with taxes on unhealthy options. The impact of prices on dietary behaviour of consumers has been demonstrated in experimental designs as well as in economic analysis of observational data on purchases. Although some experimental studies have been used to study the impact of taxation and subsidies among specific populations in France, none has evaluated the impact in the general population. Objective The aim of the study is to evaluate the impact of implementing taxes on unhealthy food and beverages and subsidies to healthy food, separately and combined, on the nutritional quality of purchases, overall and by income level, in an experimental online supermarket. Intervention description: The intervention includes taxation of lower nutritional quality products (identified using the front-of-pack nutrition label Nutri-Score - classes D and E) and/or subsidies for products of higher nutritional quality (identified as raw products or Nutri-Score A and B). Design The intervention will be a parallel arm randomized trial stratified by income against a control situation with no changes in prices and the presence of the Nutri-Score on-pack for all pre-packed products in all interventions (control, taxes and subsidies). Expected public health impact: This study will allow to investigate the potential synergistic effect on the nutritional quality of food choices of combining taxation and income-based subsidies in a context of social inequalities in rising non-communicable disease associated with poor diets. Following a proportional universalism perspective, income-based subsidies can mitigate the regressivity of taxation according to income. As no countries have implemented this combination of fiscal policies to improve diets, the results of this study will contribute to the scientific knowledge on the topic and will provide preliminary results to decision makers.

Conditions

Nutrition; Food Purchasing Intention

Keywords

Food taxation; Food subsidies

Outcome Measures

Primary Outcomes (1)

• NS-2023 NPM score

  Nutri-Score-2023 Nutrient Profile Model (NS-2023 NPM score) The NS-2023 NPM Score provides a global assessment of the nutritional quality of foods and beverages. The NS-2023 NPM score for foods and beverages is computed considering nutrient content for 100g/100ml . It allocates positive points for content in energy (KJ;0-10 points), total sugar (g ;0-15 points), saturated fatty acids (g;0-10 points) and salt (g;0-20 points). Negative points are allocated to content in fruits, vegetables, and legumes (%;0-5 points), fibers (g;0-5 points) and proteins (g;0-7 points). Final NS-2023 NPM scores are based on a discrete continuous scale ranging theoretically from -17 (most healthy) to +55 (less healthy). Overall NS-2023 NPM score of the shopping cart will be assessed using a weighted average (by Kcal) NS-2023 NPM score of the items in the shopping cart, for 100g.

  Peri-procedure (end of shopping session)

Secondary Outcomes (11)

• Energy

  Peri-procedure (end of shopping session)

• Saturated fatty acids

  Peri-procedure (end of shopping session)

• Sugars

  Peri-procedure (end of shopping session)

• Salt

  Peri-procedure (end of shopping session)

• Fibers

  Peri-procedure (end of shopping session)

Study Arms (3)

Control

NO INTERVENTION

All eligible pre-packed products labeled with Nutri-Score

Taxation

EXPERIMENTAL

Taxation of food products: 8% for products labeled as D using the front-of-package label Nutri-Score; 16% for products labeled as D using the front-of-package label Nutri-Score. All eligible pre-packed products labeled with the front-of-pack Nutri-Score

Behavioral: Taxation

Taxation + subsidies

EXPERIMENTAL

Subsidies in the form of a discount voucher of 15€/week/household member Taxation of food products: 8% for Nutri-Score D-labeled products; 16% for Nutri-Score E-labeled products. All eligible pre-packed products labeled with Nutri-Score

Behavioral: Taxation; Behavioral: Subsidies

Interventions

Taxation BEHAVIORAL

Taxation of 8% of Nutri-Score D-labeled products Taxation of 16% of Nutri-Score E-labeled products

Taxation; Taxation + subsidies

Subsidies BEHAVIORAL

Subsidies in the form of a discount voucher of 15€/household member

Taxation + subsidies

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Adult subjects (\>18 years old) included in the NutriNet-Santé cohort study from all income levels.

You may not qualify if:

• ⁃ Subjects never engaging in grocery shopping. Participants will be excluded for this based on self-reported grocery shopping frequency using a short questionnaire at the inception of the study.

Sponsors & Collaborators

• University of Paris 13: lead
• Paris School of Economics: collaborator

Study Sites (1)

Université Sorbonne Paris Nord

Bobigny, 93000, France

Location

MeSH Terms

Interventions

Taxes

Intervention Hierarchy (Ancestors)

Economics; Health Care Economics and Organizations

Central Study Contacts

Chantal Julia, MD, PhD

CONTACT

01 48 38 89 53; c.julia@eren.smbh.univ-paris13.fr

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Model Details: Parallel arm randomized trial stratified by income : * Low-income participants (\<poverty line) : three-arm parallel arms - control, taxation and taxation+subsidies * high-income participants (\>= poverty line) : two-arm parallel arms - control, taxation

Study Record Dates

• First Submitted: April 10, 2026
• First Posted: May 18, 2026
• Study Start: May 1, 2026
• Primary Completion (Estimated): September 1, 2026
• Study Completion (Estimated): September 1, 2026
• Last Updated: May 18, 2026

Record last verified: 2026-05

Data Sharing

• IPD Sharing: Will share

Locations

FR (1)