Diet, HealthyNCT05429528
Understanding Food Choices in Saudi Arabia- Taxes
A study testing Implicit Tax and Explicit Tiered Tax in people with Diet, Healthy, run by Duke-NUS Graduate Medical School at 1 site in Singapore.
Trial summary
Using a 3-arm randomized controlled trial, the investigators aim to rigorously evaluate the effects of two different taxation policies on diet quality. The first is an implicit sales tax that will be levied only on beverages in a manner that mirrors the current Kingdom of Saudi Arabia (KSA) beverage taxes and the… Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Diet, Healthy
- What is being tested?
- Implicit Tax and Explicit Tiered Tax
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 2,490 participants
- Where
- 1 siteSingapore
- Study dates
- 28 Dec 2022to 31 Jul 2023
- 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
- People who are KSA (Kingdom of Saudi Arabia) citizens
- Age of 18 and above,
- Arabic speakers, and
- A weekly primary grocery shopper for their households can participate in this study.
Who cannot join
- People who are not KSA citizens,
- Under 18 years of age,
- Cannot speak Arabic, or
- Are not weekly primary grocery shoppers for their households cannot participate in this study.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Evaluating A Promising Food Policy Intervention Using NUSMart: A Sin-Tax Scheme
Using a 3-arm randomized controlled trial, the investigators aim to rigorously evaluate the effects of two different taxation policies on diet quality. The first is an implicit sales tax that will be levied only on beverages in a manner that mirrors the current Kingdom of Saudi Arabia (KSA) beverage taxes and the second is an explicit Nutri-Score (NS) based tiered tax that is levied on all food and beverage products. The investigators will use an experimental online grocery store, called NUSMart, which is similar in design to commercial web-based grocery stores to test these two taxation policies. Participants will be randomly assigned to one of the following arms and asked to complete a one-time hypothetical shop.
Arm 1 (Control): Participants will experience a default version of NUSMart which replicates the traditional shopping experience of online grocery stores with no FOP labels.
Read more
Arm 2 (Implicit Tax): Same as Arm 1 NUSMart except that an implicit tax will be levied only on beverages: a 50% sales tax on carbonated drinks and sugar-sweetened beverages (SSBs) and 100% tax on energy drinks (milk, milk-based products, and natural fruit juice are excluded).
Arm 3 (Explicit Tiered Tax): Same as Arm 1 NUSMart except that an explicit tiered tax based on (underlying) NS is levied on (sale price of) all food and beverages. NS assesses overall nutritional quality of products on the basis of 7 nutrients (calories, saturated fats, sugar, salt, fiber, protein and percentage of fruits, vegetables and nuts) from A to E (best to worst). In this arm, the investigators implement a 20% sales tax on the retail price for NS D beverages and 10% for NS D foods along with a 50% sales tax on NS E beverages and 20% on NS E foods.
The investigators hypothesize the following:
Hypothesis 1: Diet quality of food purchases, measured by the weighted average Nutri-Score point, will be highest in the explicit tiered tax arm, followed by the implicit tax arm, followed by the control.
Hypothesis 2: Average calories, sugar, sodium, and saturated fat per serving will be lowest in the explicit tiered tax arm, followed by the implicit tax arm, followed by the control.
Read the detailed description
Experimental design \& procedures
The aim of this study is to use a 3-arm randomized controlled trial with an online grocery store known as NUSMart, to rigorously evaluate the effect of two different taxation policies i.e., implicit tax on select beverages and an explicit tiered tax on all products, on diet quality.
- Tax Strategies The investigators tested 2 different types of taxation strategies in this study. They are as follows:
- Implicit Tax: This will be levied only on certain beverage categories: a 50% sales tax on carbonated drinks and sugar-sweetened beverages (SSBs) and 100% tax on energy drinks (milk, milk-based products, and natural fruit juice are excluded).
- Explicit Tiered Tax: This is an explicit tiered tax based on (underlying) Nutri-Score (NS) grades which will be levied on all food and beverages. In this arm, the investigators implement a 20% sales tax on the retail price for NS D beverages and 10% for NS D foods along with a 50% sales tax on NS E beverages and 20% on NS E foods. The NS labels will not be displayed.
- Overview of RCT Design To test these labels, the investigators used three different versions of NUSMart. Each participant was randomly assigned to one of the following arms and asked to complete a one-time hypothetical shop. Arm 1: Control arm. Participants experience an unmodified version of NUSMart, which replicates the traditional shopping experience of online grocery stores. Arm 2: Similar to Arm 1 except that an implicit tax is levied on qualifying beverages. Arm 3: Similar to Arm 1 except that an explicit tiered tax is levied on qualifying food and beverage products. To minimize hypothetical shopping biases, the investigators set a minimum spending value per person per week and adjusted the total minimum spending value depending on household size. Additionally, participants will have to shop from 4 different NUSMart categories and purchase at least one beverage product to be able to successfully checkout their cart. Finally, participants will be told that there is up to a 50% probability that they will be asked to actually purchase the items in their final checked-out cart when in reality they will never be asked to make any purchase.
- Subject related procedures
As the investigators have done in prior studies, participants will be recruited if they are KSA residents aged 18 years or older, can speak Arabic and are primary weekly shoppers for their households. Recruitment will be done through Facebook advertisements boosted using an automation tool called Revealbot to help optimise workflow.
On recruitment, they will be asked to fill in a baseline questionnaire to collect demographic and health characteristics, which should take approximately 10-15 minutes to complete. The baseline questionnaire includes a question as to whether any household members have a medical condition, such as diabetes or hypertension, which requires limiting the types of foods they eat. Investigators ask this question to allow for testing whether the interventions differentially influence these households, with the expectation that households with less healthy patients may obtain greater benefits from purchasing baskets with higher mean Nutri-Scores. Since the objective of this randomized control trail (RCT) is to quantify the effectiveness of the interventions on diet quality, a precursor to NCDs, the collection of household health indicators is reasonable.
Upon completion of the baseline survey, participants will be randomly assigned to one of the 3 shopping conditions (Arm 1 [Control], Arm 2, or Arm 3) and redirected to NUSMart to log in and begin shopping immediately.
On NUSMart, they will be asked to purchase their weekly groceries with a minimum spend of SAR 75 (equivalent to 20 USD) per person per week (the total minimum spending value will depend on the household size). Each participant will therefore shop only once during the study in one of the arms (1, 2 or 3) which will be randomly assigned to them.
Participants will be given explicit instructions to purchase groceries for the purposes of breakfast, lunch, dinner, snacks, and beverage consumption for one week keeping in mind that they will not be consuming any meals outside. The stores will be set up such that participants will not be allowed to check out with their cart unless they have selected items from 4 different NUSMart categories and purchase at least one beverage. This is to ensure that participants shop as though they are shopping for their own consumption i.e., to minimize hypothetical biases. As mentioned earlier, participants will be reminded that there is up to a 50% probability that they will be asked to actually purchase the products in the final cart they check out from the store.
A post-study survey will be conducted after the shop to collect participant opinions on the labels and understand their impact better.
- Conditions
- Diet, Healthy
- Being tested
- Implicit Tax, Explicit Tiered Tax
- Keywords
- Implicit/ Explicit Tax, Sugar-sweetened beverages tax, Diet quality, Online grocery shopping, Kingdom of Saudi Arabia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Implicit TaxBehavioural
This will be levied only on certain beverage categories: a 50% tax on the sales prices of carbonated drinks and sugar-sweetened beverages (SSBs) and 100% tax on the sales prices of energy drinks (milk, milk-based products, and natural fruit juice are excluded).
Explicit Tiered TaxBehavioural
This is an explicit tiered tax based on (underlying) Nutri-Score (NS) grades which will be levied on all food and beverages. In this arm, the investigators implement a 20% sales tax on the retail price for NS D beverages and 10% for NS D foods along with a 50% sales tax on NS E beverages and 20% on NS E foods. The NS labels will not be displayed.
| Study group | Role | What they receive |
|---|---|---|
| Control Arm (Arm 1) | No intervention | Participants will experience a default version of NUSMart which replicates the traditional shopping experience of online grocery stores with no FOP labels. |
| Implicit Tax Arm (Arm 2) | Experimental | Similar to Arm 1 except that an implicit tax is levied on qualifying beverages. Receives: Behavioral: Implicit Tax |
| Explicit Tiered Tax Arm (Arm 3) | Experimental | Similar to Arm 1 except that an explicit tiered tax is levied on qualifying food and beverage products. Receives: Behavioral: Explicit Tiered Tax |
What is being measured
The primary outcome is the main question the study is designed to answer.
Value of Nutri-Score
Diet quality measured by the weighted (by the number of servings) average of all purchased products' Nutri-Score for the shopping trip. Nutri-Score is a holistic dietary index based on the British Food Standard Agency Nutrient Profiling System that grades food and beverage products from A to E where A indicates the highest nutritional quality and E indicates the lowest nutritional quality.
Measured: After completion of data collection, an average of about 5 months
Secondary outcomes (1)
Quantity of other Nutrients
calories per serving, grams of sugars per serving, milligrams of sodium per serving, grams of saturated fat per serving.
Measured: After completion of data collection, an average of about 5 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Jun 2022
- Study start28 Dec 2022
- Primary completion31 Jul 2023
- Study completion31 Jul 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Diet, HealthyStudies 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
- Health services research
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 2,490 participants (actual)
Sponsor and investigators
- Lead sponsor
- Duke-NUS Graduate Medical School
- Sponsor type
- University, hospital or other
- Collaborators
- World Bank, Public Health Authority of Saudi Arabia
- Responsible party
- Principal investigator, Eric A. Finkelstein, Duke-NUS Graduate Medical School
- Investigators
- Eric A Finkelstein, PhD MHA, Principal investigator, Duke-NUS Graduate Medical School
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05429528
- Sponsor's protocol ID
- 7202186
- Status last verified
- Oct 2023
- First submitted
- 19 Jun 2022
- Last updated
- 23 Oct 2023
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 23 Oct 2023. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluating A Promising Food Policy Intervention Using NUSMart: A Sin-Tax Scheme
- ClinicalTrials.gov ID
- NCT05429528
- Acronym / sponsor ID
- 7202186
- Conditions
- Diet, Healthy
- Keywords
- Implicit/ Explicit Tax, Sugar-sweetened beverages tax, Diet quality, Online grocery shopping, Kingdom of Saudi Arabia
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 2,490 participants (actual)
- Lead sponsor
- Duke-NUS Graduate Medical SchoolUniversity, hospital or other
- Collaborators
- World Bank, Public Health Authority of Saudi Arabia
- Study start
- 28 Dec 2022 (actual)
- Primary completion
- 31 Jul 2023 (actual)
- Study completion
- 31 Jul 2023 (actual)
- First posted
- 23 Jun 2022 (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.
Using a 3-arm randomized controlled trial, the investigators aim to rigorously evaluate the effects of two different taxation policies on diet quality. The first is an implicit sales tax that will be levied only on beverages in a manner that mirrors the current Kingdom of Saudi Arabia (KSA) beverage taxes and the second is an explicit Nutri-Score (NS) based tiered tax that is levied on all food and beverage products. The investigators will use an experimental online grocery store, called NUSMart, which is similar in design to commercial web-based grocery stores to test these two taxation policies. Participants will be randomly assigned to one of the following arms and asked to complete a one-time hypothetical shop.
Arm 1 (Control): Participants will experience a default version of NUSMart which replicates the traditional shopping experience of online grocery stores with no FOP labels.
Arm 2 (Implicit Tax): Same as Arm 1 NUSMart except that an implicit tax will be levied only on beverages: a 50% sales tax on carbonated drinks and sugar-sweetened beverages (SSBs) and 100% tax on energy drinks (milk, milk-based products, and natural fruit juice are excluded).
Arm 3 (Explicit Tiered Tax): Same as Arm 1 NUSMart except that an explicit tiered tax based on (underlying) NS is levied on (sale price of) all food and beverages. NS assesses overall nutritional quality of products on the basis of 7 nutrients (calories, saturated fats, sugar, salt, fiber, protein and percentage of fruits, vegetables and nuts) from A to E (best to worst). In this arm, the investigators implement a 20% sales tax on the retail price for NS D beverages and 10% for NS D foods along with a 50% sales tax on NS E beverages and 20% on NS E foods.
The investigators hypothesize the following:
Hypothesis 1: Diet quality of food purchases, measured by the weighted average Nutri-Score point, will be highest in the explicit tiered tax arm, followed by the implicit tax arm, followed by the control.
Hypothesis 2: Average calories, sugar, sodium, and saturated fat per serving will be lowest in the explicit tiered tax arm, followed by the implicit tax arm, followed by the control.
Detailed description
Experimental design \& procedures
The aim of this study is to use a 3-arm randomized controlled trial with an online grocery store known as NUSMart, to rigorously evaluate the effect of two different taxation policies i.e., implicit tax on select beverages and an explicit tiered tax on all products, on diet quality.
- Tax Strategies The investigators tested 2 different types of taxation strategies in this study. They are as follows:
- Implicit Tax: This will be levied only on certain beverage categories: a 50% sales tax on carbonated drinks and sugar-sweetened beverages (SSBs) and 100% tax on energy drinks (milk, milk-based products, and natural fruit juice are excluded).
- Explicit Tiered Tax: This is an explicit tiered tax based on (underlying) Nutri-Score (NS) grades which will be levied on all food and beverages. In this arm, the investigators implement a 20% sales tax on the retail price for NS D beverages and 10% for NS D foods along with a 50% sales tax on NS E beverages and 20% on NS E foods. The NS labels will not be displayed.
- Overview of RCT Design To test these labels, the investigators used three different versions of NUSMart. Each participant was randomly assigned to one of the following arms and asked to complete a one-time hypothetical shop. Arm 1: Control arm. Participants experience an unmodified version of NUSMart, which replicates the traditional shopping experience of online grocery stores. Arm 2: Similar to Arm 1 except that an implicit tax is levied on qualifying beverages. Arm 3: Similar to Arm 1 except that an explicit tiered tax is levied on qualifying food and beverage products. To minimize hypothetical shopping biases, the investigators set a minimum spending value per person per week and adjusted the total minimum spending value depending on household size. Additionally, participants will have to shop from 4 different NUSMart categories and purchase at least one beverage product to be able to successfully checkout their cart. Finally, participants will be told that there is up to a 50% probability that they will be asked to actually purchase the items in their final checked-out cart when in reality they will never be asked to make any purchase.
- Subject related procedures
As the investigators have done in prior studies, participants will be recruited if they are KSA residents aged 18 years or older, can speak Arabic and are primary weekly shoppers for their households. Recruitment will be done through Facebook advertisements boosted using an automation tool called Revealbot to help optimise workflow.
On recruitment, they will be asked to fill in a baseline questionnaire to collect demographic and health characteristics, which should take approximately 10-15 minutes to complete. The baseline questionnaire includes a question as to whether any household members have a medical condition, such as diabetes or hypertension, which requires limiting the types of foods they eat. Investigators ask this question to allow for testing whether the interventions differentially influence these households, with the expectation that households with less healthy patients may obtain greater benefits from purchasing baskets with higher mean Nutri-Scores. Since the objective of this randomized control trail (RCT) is to quantify the effectiveness of the interventions on diet quality, a precursor to NCDs, the collection of household health indicators is reasonable.
Upon completion of the baseline survey, participants will be randomly assigned to one of the 3 shopping conditions (Arm 1 [Control], Arm 2, or Arm 3) and redirected to NUSMart to log in and begin shopping immediately.
On NUSMart, they will be asked to purchase their weekly groceries with a minimum spend of SAR 75 (equivalent to 20 USD) per person per week (the total minimum spending value will depend on the household size). Each participant will therefore shop only once during the study in one of the arms (1, 2 or 3) which will be randomly assigned to them.
Participants will be given explicit instructions to purchase groceries for the purposes of breakfast, lunch, dinner, snacks, and beverage consumption for one week keeping in mind that they will not be consuming any meals outside. The stores will be set up such that participants will not be allowed to check out with their cart unless they have selected items from 4 different NUSMart categories and purchase at least one beverage. This is to ensure that participants shop as though they are shopping for their own consumption i.e., to minimize hypothetical biases. As mentioned earlier, participants will be reminded that there is up to a 50% probability that they will be asked to actually purchase the products in the final cart they check out from the store.
A post-study survey will be conducted after the shop to collect participant opinions on the labels and understand their impact better.
Study design
- Primary purpose
- Health services research
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Control Arm (Arm 1) | No intervention | –Participants will experience a default version of NUSMart which replicates the traditional shopping experience of online grocery stores with no FOP labels. |
| Implicit Tax Arm (Arm 2) | Experimental | Behavioral: Implicit TaxSimilar to Arm 1 except that an implicit tax is levied on qualifying beverages. |
| Explicit Tiered Tax Arm (Arm 3) | Experimental | Behavioral: Explicit Tiered TaxSimilar to Arm 1 except that an explicit tiered tax is levied on qualifying food and beverage products. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- People who are KSA (Kingdom of Saudi Arabia) citizens
- Age of 18 and above,
- Arabic speakers, and
- A weekly primary grocery shopper for their households can participate in this study.
Key exclusion criteria (4 listed)
- People who are not KSA citizens,
- Under 18 years of age,
- Cannot speak Arabic, or
- Are not weekly primary grocery shoppers for their households cannot participate in this study.
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 |
|---|---|---|
| Implicit TaxThis will be levied only on certain beverage categories: a 50% tax on the sales prices of carbonated drinks and sugar-sweetened beverages (SSBs) and 100% tax on the sales prices of energy drinks (milk, milk-based products, and natural fruit juice are excluded). | Behavioural | Implicit Tax Arm (Arm 2) |
| Explicit Tiered TaxThis is an explicit tiered tax based on (underlying) Nutri-Score (NS) grades which will be levied on all food and beverages. In this arm, the investigators implement a 20% sales tax on the retail price for NS D beverages and 10% for NS D foods along with a 50% sales tax on NS E beverages and 20% on NS E foods. The NS labels will not be displayed. | Behavioural | Explicit Tiered Tax Arm (Arm 3) |
Primary outcome
Value of Nutri-Score
Time frame: After completion of data collection, an average of about 5 months
Diet quality measured by the weighted (by the number of servings) average of all purchased products' Nutri-Score for the shopping trip. Nutri-Score is a holistic dietary index based on the British Food Standard Agency Nutrient Profiling System that grades food and beverage products from A to E where A indicates the highest nutritional quality and E indicates the lowest nutritional quality.
1 secondary outcome
Quantity of other Nutrients
Time frame: After completion of data collection, an average of about 5 months
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 23 Oct 2023.
- Individual participant dataSharing planned: No
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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.
Eric A Finkelstein, PhD MHA principal investigator
Duke-NUS Graduate Medical School
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Implicit Tax and Explicit Tiered Tax in people with Diet, Healthy, run by Duke-NUS Graduate Medical School at 1 site in Singapore.
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 4 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 23 Oct 2023. 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 Singapore. 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?
Value of Nutri-Score (time frame: After completion of data collection, an average of about 5 months). 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 23 Oct 2023.