Behavior: Healthy Food ChoiceNCT07842380
Effects of Just-In-Time Food Swap Recommendations
A study testing JIT Visibility Only Nudge, Descriptive Nutritional Labelling Nudge. and Hedonic Enhancement Nudge in people with Behavior: Healthy Food Choice, run by Tilburg University at 1 site in Netherlands.
Trial summary
This study used a randomized five-condition experiment in a mock online supermarket to investigate whether just-in-time (JIT) food-swap recommendations can improve the healthiness of food choices and whether different types of justification: visibility-only, descriptive/normative language (DNL), social norms, and… Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Behavior: Healthy Food Choice
- What is being tested?
- JIT Visibility Only Nudge, Descriptive Nutritional Labelling Nudge. and Hedonic Enhancement Nudge
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 607 participants
- Where
- 1 siteNetherlands
- Study dates
- 25 Nov 2025to 22 Dec 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- being fluent in the Dutch language
- have a smartphone
Who cannot join
- no dietary restrictions
- not complete the shopping task or final questionnaire
- very short or long completion times
- Participants must pass at least one of two attention checks
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Individual Traits and Food Choice Nudges: Exploring How Socioeconomic and Personal Factors Shape Nudge Effectiveness Across Different Nudge Types
This study used a randomized five-condition experiment in a mock online supermarket to investigate whether just-in-time (JIT) food-swap recommendations can improve the healthiness of food choices and whether different types of justification: visibility-only, descriptive/normative language (DNL), social norms, and hedonic enhancement, affect recommendation acceptance and food choice healthiness. The study also examined the psychological mechanisms underlying these effects, focusing on ethe ease of identifying healthy options (EIHO) as a facilitating mechanism and psychological reactance as a potential barrier, and explored whether effects varied by socioeconomic position, food choice motives, and decision-making styles. Ultimately, the study aimed to identify personalization approaches that can make JIT food-swap recommendations effective across the socioeconomic gradient.
Read the detailed description
This study employed a between-subjects design with one factor (JIT justification type) and five levels/conditions: no recommendation; JIT visibility-only (recommendation without justification); DNL; social norm; and hedonic enhancement. Acceptance rate and healthiness of food choices were the primary outcome variables. Participants were randomly assigned to one of the conditions and then completed a hypothetical grocery-shopping task using MAND, a mock supermarket app developed by NAKKO. Psychological reactance and ease of identifying healthier options (EIHO) were included as mediating variables. General decision-making style (GDMS), food choice motive (FCM), education level, and subjective socioeconomic position were included as moderating variables. This study was approved by the Ethical Review Board of the Tilburg School of Humanities and Digital Sciences (Identification code: REDC2023.34abc).
The study was conceptually divided into two models for theoretical clarity. Model 1 (The JIT Presence Mediation Model) focused on the effects of the JIT visibility-only recommendation (versus no JIT) on healthiness of food choices. Model 2 (JIT Justification Type Moderation Model) focused on the effects of JIT justification types (DNL, hedonic enhancement, social norms versus JIT visibility-only recommendation) on acceptance rate. Our hypotheses are visualized in the conceptual models 1 and model 2 and were preregistered at the Open Science Framework (osf.io/y29ha). The hypotheses and models differ from the original preregistration only in their numbering, which was revised to clarify and separate the models, and in minor rewording for clarity.
Aims:
The study aimed to examine the effects of different Just-In-Time food-swap recommendations on healthiness of food choices (model 1) and on acceptance rate (model 2). The study also explored the facilitating (ease of identifying healthier options) and hindering (psychological reactance) underlying mechanisms, and whether they differed by SEP, domain-general (GDMS) and food-specific (FCM) individual characteristics. Lastly, the study aimed to contribute to identifying personalization approaches that could make JIT food swap recommendations effective across the socioeconomic gradient
- Conditions
- Behavior: Healthy Food Choice
- Being tested
- No Nudge (control), JIT Visibility Only Nudge, Descriptive Nutritional Labelling Nudge., Hedonic Enhancement Nudge, Social Norm Nudge
- Keywords
- food choice, retail environment, food purchasing, reactance, ease of identifying healthy options, online supermarket
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
No Nudge (control)Other
No Nudge. Participants are not presented with a pop-up showing a suggested alternative. After making their selection, they are immediately routed back to the start screen, where they can click on the next product category.
JIT Visibility Only NudgeOther
An alternative product (image, product name, and price) is suggested in the pop-up, accompanied by a header that reads "Alternative".
Descriptive Nutritional Labelling Nudge.Other
This nudge is the same as the JIT visibility only nudge condition, but with an additional text providing health information on the alternative compared to the original choice (e.g., "This product contains less salt").
Hedonic Enhancement NudgeOther
This nudge is the same as the JIT visibility only nudge condition, but with an additional descriptive text (e.g., "Delicious and refreshing"). Furthermore, the product image is replaced with an enhanced version that highlights the product's taste and visual appeal.
Social Norm NudgeOther
This nudge is the same as the JIT visibility only nudge condition, but with an additional descriptive prompt (e.g., "4 out of 5 people chose this") and a visual representation.
| Study group | Role | What they receive |
|---|---|---|
| No Nudge (control) | Experimental | Participants are not presented with a pop-up showing a suggested alternative. After making their selection, they are immediately routed back to the start screen, where they can click on the next product category. Receives: Other: No Nudge (control) |
| JIT Visibility Only Nudge | Experimental | An alternative product (image, product name, and price) is suggested in the pop-up, accompanied by a header that reads "Alternative" Receives: Other: JIT Visibility Only Nudge |
| Descriptive Nutritional Labelling Nudge | Experimental | This nudge is the same as the JIT visibility only nudge condition, but with an additional text providing health information on the alternative compared to the original choice (e.g., "This product contains less salt"). Receives: Other: Descriptive Nutritional Labelling Nudge. |
| Hedonic Enhancement Nudge | Experimental | This nudge is the same as the JIT visibility only nudge condition, but with an additional descriptive text (e.g., "Delicious and refreshing"). Furthermore, the product image is replaced with an enhanced version that highlights the product's taste and visual appeal. Receives: Other: Hedonic Enhancement Nudge |
| Social Norm Nudge | Experimental | This nudge is the same as the JIT visibility only nudge condition, but with an additional descriptive prompt (e.g., "4 out of 5 people chose this") and a visual representation. Receives: Other: Social Norm Nudge |
What is being measured
The primary outcome is the main question the study is designed to answer.
Healthiness of Food Choices (basket healthiness)
The healthiness of each participant's final basket (i.e., after the possibility to swap before final checkout) was measured by using the FNS score of each product and calculating the average score of the six products they selected for experimental product categories. The FNS score ranges from -15 to +40. A smaller average FNS score means healthier food choices.
Measured: During the retail application session
Acceptance rate
Recommendation acceptance rate was measured as the proportion of recommendations accepted during experimental trials, calculated as the number of accepted recommendations divided by the total number of recommendations presented (ranging from 3 to 6).
Measured: During the retail application session
Secondary outcomes (2)
Ease of Identifying Healthier Options (EIHO)
EIHO was assessed by one question asking participants how easy it was to identify healthy products during the grocery shopping task. Responses were recorded on a 7-point Likert scale, ranging from 1 = "Not easy at all" to 7 = "Very easy", with higher scores indicating greater ease in identifying the healthier options [1].
Measured: immediately after the intervention
Psychological Reactance
Psychological reactance was measured using four items assessing anger (e.g., "This app made me feel irritated") and four items assessing perceived threat to freedom (e.g., "I felt like my choices were being restricted"). Participants responded on a 5-point Likert scale, ranging from 1 = "Strongly disagree" to 5 = "Strongly agree." Scores were calculated by averaging responses across items, with higher scores indicating greater psychological reactance (α = .87)
Measured: immediately after the intervention
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 Sep 2026
- Study start25 Nov 2025
- Primary completion22 Dec 2025
- Study completion22 Dec 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Behavior: Healthy Food ChoiceStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- This study used an online one-factor, five-level between-subjects design (No recommendation vs. JIT visibility-only vs. descriptive nutritional label (DNL) vs. social norm vs. hedonic enhancement) with acceptance rate and food choice healthiness as the main dependent variables and JIT recommendation presence and Justification type as the main independent variables. The analyses is conceptually divided into Model 1 (The JIT recommendation Presence Mediation Model) where we focus on the effects of the JIT visibility-only recommendation (versus no recommendation) and Model 2 (The JIT Justification Type Moderation Model), where the focus is on the effects of the additional justifications (DNL, hedonic enhancement, social norms) to a JIT recommendation compared to a JIT visibility-only recommendation with no justification. The study is structured in this two-stage way for theoretical clarity.
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 607 participants (actual)
Sponsor and investigators
- Lead sponsor
- Tilburg University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Laura Nynke van der Laan, Tilburg University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07842380
- Sponsor's protocol ID
- REDC2023.34abc
- Status last verified
- Sep 2026
- First submitted
- 15 Sep 2026
- Last updated
- 25 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Data will be shared via the organisation's data repository - Dataverse
Study at a glance
From the registry record, last updated by the sponsor on 25 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Individual Traits and Food Choice Nudges: Exploring How Socioeconomic and Personal Factors Shape Nudge Effectiveness Across Different Nudge Types
- ClinicalTrials.gov ID
- NCT07842380
- Acronym / sponsor ID
- REDC2023.34abc
- Conditions
- Behavior: Healthy Food Choice
- Keywords
- food choice, retail environment, food purchasing, reactance, ease of identifying healthy options, online supermarket
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 607 participants (actual)
- Lead sponsor
- Tilburg UniversityUniversity, hospital or other
- Study start
- 25 Nov 2025 (actual)
- Primary completion
- 22 Dec 2025 (actual)
- Study completion
- 22 Dec 2025 (actual)
- First posted
- 25 Sep 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study used a randomized five-condition experiment in a mock online supermarket to investigate whether just-in-time (JIT) food-swap recommendations can improve the healthiness of food choices and whether different types of justification: visibility-only, descriptive/normative language (DNL), social norms, and hedonic enhancement, affect recommendation acceptance and food choice healthiness. The study also examined the psychological mechanisms underlying these effects, focusing on ethe ease of identifying healthy options (EIHO) as a facilitating mechanism and psychological reactance as a potential barrier, and explored whether effects varied by socioeconomic position, food choice motives, and decision-making styles. Ultimately, the study aimed to identify personalization approaches that can make JIT food-swap recommendations effective across the socioeconomic gradient.
Detailed description
This study employed a between-subjects design with one factor (JIT justification type) and five levels/conditions: no recommendation; JIT visibility-only (recommendation without justification); DNL; social norm; and hedonic enhancement. Acceptance rate and healthiness of food choices were the primary outcome variables. Participants were randomly assigned to one of the conditions and then completed a hypothetical grocery-shopping task using MAND, a mock supermarket app developed by NAKKO. Psychological reactance and ease of identifying healthier options (EIHO) were included as mediating variables. General decision-making style (GDMS), food choice motive (FCM), education level, and subjective socioeconomic position were included as moderating variables. This study was approved by the Ethical Review Board of the Tilburg School of Humanities and Digital Sciences (Identification code: REDC2023.34abc).
The study was conceptually divided into two models for theoretical clarity. Model 1 (The JIT Presence Mediation Model) focused on the effects of the JIT visibility-only recommendation (versus no JIT) on healthiness of food choices. Model 2 (JIT Justification Type Moderation Model) focused on the effects of JIT justification types (DNL, hedonic enhancement, social norms versus JIT visibility-only recommendation) on acceptance rate. Our hypotheses are visualized in the conceptual models 1 and model 2 and were preregistered at the Open Science Framework (osf.io/y29ha). The hypotheses and models differ from the original preregistration only in their numbering, which was revised to clarify and separate the models, and in minor rewording for clarity.
Aims:
The study aimed to examine the effects of different Just-In-Time food-swap recommendations on healthiness of food choices (model 1) and on acceptance rate (model 2). The study also explored the facilitating (ease of identifying healthier options) and hindering (psychological reactance) underlying mechanisms, and whether they differed by SEP, domain-general (GDMS) and food-specific (FCM) individual characteristics. Lastly, the study aimed to contribute to identifying personalization approaches that could make JIT food swap recommendations effective across the socioeconomic gradient
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 5
- Model description
- This study used an online one-factor, five-level between-subjects design (No recommendation vs. JIT visibility-only vs. descriptive nutritional label (DNL) vs. social norm vs. hedonic enhancement) with acceptance rate and food choice healthiness as the main dependent variables and JIT recommendation presence and Justification type as the main independent variables. The analyses is conceptually divided into Model 1 (The JIT recommendation Presence Mediation Model) where we focus on the effects of the JIT visibility-only recommendation (versus no recommendation) and Model 2 (The JIT Justification Type Moderation Model), where the focus is on the effects of the additional justifications (DNL, hedonic enhancement, social norms) to a JIT recommendation compared to a JIT visibility-only recommendation with no justification. The study is structured in this two-stage way for theoretical clarity.
| Arm | Type | Receives |
|---|---|---|
| No Nudge (control) | Experimental | Other: No Nudge (control)Participants are not presented with a pop-up showing a suggested alternative. After making their selection, they are immediately routed back to the start screen, where they can click on the next product category. |
| JIT Visibility Only Nudge | Experimental | Other: JIT Visibility Only NudgeAn alternative product (image, product name, and price) is suggested in the pop-up, accompanied by a header that reads "Alternative" |
| Descriptive Nutritional Labelling Nudge | Experimental | Other: Descriptive Nutritional Labelling Nudge.This nudge is the same as the JIT visibility only nudge condition, but with an additional text providing health information on the alternative compared to the original choice (e.g., "This product contains less salt"). |
| Hedonic Enhancement Nudge | Experimental | Other: Hedonic Enhancement NudgeThis nudge is the same as the JIT visibility only nudge condition, but with an additional descriptive text (e.g., "Delicious and refreshing"). Furthermore, the product image is replaced with an enhanced version that highlights the product's taste and visual appeal. |
| Social Norm Nudge | Experimental | Other: Social Norm NudgeThis nudge is the same as the JIT visibility only nudge condition, but with an additional descriptive prompt (e.g., "4 out of 5 people chose this") and a visual representation. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- being fluent in the Dutch language
- have a smartphone
Key exclusion criteria (4 listed)
- no dietary restrictions
- not complete the shopping task or final questionnaire
- very short or long completion times
- Participants must pass at least one of two attention checks
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| No Nudge (control)No Nudge. Participants are not presented with a pop-up showing a suggested alternative. After making their selection, they are immediately routed back to the start screen, where they can click on the next product category. | Other | No Nudge (control) |
| JIT Visibility Only NudgeAn alternative product (image, product name, and price) is suggested in the pop-up, accompanied by a header that reads "Alternative". | Other | JIT Visibility Only Nudge |
| Descriptive Nutritional Labelling Nudge.This nudge is the same as the JIT visibility only nudge condition, but with an additional text providing health information on the alternative compared to the original choice (e.g., "This product contains less salt"). | Other | Descriptive Nutritional Labelling Nudge |
| Hedonic Enhancement NudgeThis nudge is the same as the JIT visibility only nudge condition, but with an additional descriptive text (e.g., "Delicious and refreshing"). Furthermore, the product image is replaced with an enhanced version that highlights the product's taste and visual appeal. | Other | Hedonic Enhancement Nudge |
| Social Norm NudgeThis nudge is the same as the JIT visibility only nudge condition, but with an additional descriptive prompt (e.g., "4 out of 5 people chose this") and a visual representation. | Other | Social Norm Nudge |
Primary outcome
Healthiness of Food Choices (basket healthiness)
Time frame: During the retail application session
The healthiness of each participant's final basket (i.e., after the possibility to swap before final checkout) was measured by using the FNS score of each product and calculating the average score of the six products they selected for experimental product categories. The FNS score ranges from -15 to +40. A smaller average FNS score means healthier food choices.
Acceptance rate
Time frame: During the retail application session
Recommendation acceptance rate was measured as the proportion of recommendations accepted during experimental trials, calculated as the number of accepted recommendations divided by the total number of recommendations presented (ranging from 3 to 6).
2 secondary outcomes
Ease of Identifying Healthier Options (EIHO)
Time frame: immediately after the intervention
Psychological Reactance
Time frame: immediately after the intervention
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 25 Sep 2026.
- Individual participant dataSharing planned: No. Data will be shared via the organisation's data repository - Dataverse
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing JIT Visibility Only Nudge, Descriptive Nutritional Labelling Nudge. and Hedonic Enhancement Nudge in people with Behavior: Healthy Food Choice, run by Tilburg University at 1 site in Netherlands.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 25 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Netherlands. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Healthiness of Food Choices (basket healthiness) (time frame: During the retail application session). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 25 Sep 2026.