Understanding Grocery Shopping Behaviour

A Randomized Trial and Impact Evaluation of Singapore's New Food Labels Aimed to Address the War on Diabetes

This study aims to systematically evaluate the effect of Singapore's new front-of-pack non-alcoholic beverage labels, called Nutri-Grade, on the consumption of processed beverages. Using a fully functional grocery webstore, the investigators wish to assess the causal effect of the new labels on food and beverage purchase, sugar intake, and overall diet quality and examine how this effect varies by shoppers' income and education level.

The investigators' hypotheses about the effects of these new food labels, measured by the grams of sugar per serving (primary) of finalized shopping baskets, are as follows:

1. Hypotheses 1: The new sugar-sweetened beverage (SSB) labels will shift consumers toward healthier products. Sugar-sweetened beverages are any liquids that have been sweetened with one or more of the different forms of added sugars.
2. Hypotheses 2: The new SSB labels will reduce overall sugar and calories purchased and increase overall diet quality.
3. Hypotheses 3: Effects will be greater for those with low income/low education as they are least familiar with the nutrition facts panel and thus most likely to benefit from the new information.

Study Overview

• Status: Completed
• Conditions: Diet Quality
• Intervention / Treatment: Behavioral: Nutri-Grade labels

Detailed Description

1. Experimental Design and Procedures

   The aim of this study is to use a 2 x 2 within-subject crossover design with an online grocery store, to systematically evaluate the effect of the new SSB front-of-pack labels, Nutri-Grade, on diet quality and examine how this effect varies by shoppers' income and education level. To this end, the investigators will be using two different versions of an online experimental grocery store called NUSMart, designed for research purposes. The two versions are described below.

2. Overview of Experimental Design

The investigators will recruit Singapore residents aged 21 years or older. Prospective participants will be asked to complete an online screener to determine their eligibility to participate in the study. Those who do not consent or are deemed ineligible will be notified of their ineligibility with an on-screen message.

If interested and eligible, the applicant will then be asked to complete a registration form containing name, mobile number, and email address. Contact information for the Duke-NUS study team will be provided to allow questions to be asked at any point in the consent process and throughout the study. Upon completion of the registration form, NUSMart will create the participant account and a unique ID number (CID) for use throughout the study. Participants will receive an automated email with their unique login details.

Participants will be directed to read the Participant Information Sheet and provide consent. The investigators will provide information on study protocols and participation details without disclosing the intervention arms explicitly, to maintain the integrity of participant responses and hence to ensure validity of results. It will be deleterious to the study to reveal the labels or the differences between study arms before participants complete both shops as this will likely confound participant responses. The consent form will state that in each of the shops there is a 50% chance that the participant will have to make actual purchases i.e. buy the groceries in the cart they checked out. In reality, it will be randomly decided earlier whether shopping trip 1 or 2 is the real shop. This will be achieved via a collaboration with a local online grocery provider, FairPrice.

After obtaining consent, participants will be asked to fill in a baseline survey to collect demographic and health characteristics. 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.

Eligible participants who have completed to this point will enter a participant waiting list, where the study team will manually enroll the participant as active according to the capacity of the study team. Once participants have successfully enrolled in the study they will be informed by email, and are expected to complete two grocery shops (one shop per week) on NUSMart. Participants are expected to complete one shop in one sitting. The investigators will apply a within person design and randomize the order of the two shops. Participants will receive email and text reminders each week to complete their order.

Each participant will be told that they must buy at least one beverage product and that they will make the payment using their credit card & receive their grocery orders. This real-shopping experiment ensures the credibility of the results. Each participant will therefore shop a total of 2 times during the study. This will include 1 shop within each shopping condition (Arm 1 and Arm 2).

During the study, participants will be asked to purchase their weekly groceries the amount of which is similar to their typical grocery shopping for their households, with a specified minimum spend at each shop. A wheel of purchase will be used to determine which one of the 2 shops will the participant actually pay for and receive ordered goods for. Upon completion of their second shop, participants will be asked to fill in a short post-study survey asking for their feedback on the interventions. Participants who successfully complete both shops and all other surveys will be considered as having completed the study. Participants will be provided with the debriefing sheet via email after study completion. For the participants who wish to withdraw midway into the study, the debriefing sheet will be sent to them as soon as possible after they withdraw.

• Study Type: Interventional
• Enrollment (Actual): 110
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Singapore
  • Singapore, Singapore, 169857
    • Duke-NUS Graduate Medical School

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Singapore resident
• Age 21 and above
• Must be the primary weekly grocery shopper in their household
• Must have an account with our appointed online grocery service provider or is willing to create one.

Exclusion Criteria:

• Non-Singapore resident
• Non-primary grocery shopper in their household
• Less than 21 years old
• Doesn't have an account with our appointed online grocery service provider and is unwilling to create one.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Health Services Research
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Arm 1 (Control Arm); A default NUSMart that mirrors a conventional web-grocery store in Singapore where some healthier products are displayed with Singapore's Healthier Choice Symbol (HCS) logos (Control).
Experimental: Arm 2 (Nutri-Grade Arm); Similar to Arm 1 except that beverages will be displayed with a color-coded and graded Nutri-Grade label.	Behavioral: Nutri-Grade labels; All beverage products in the arm are displayed with the Nutri-Grade label. This label was proposed by the Ministry of Health in Singapore to be implemented at the end of 2021. It will apply to all pre-packaged non-alcoholic beverages sold in Singapore. It will have four color-coded grades wherein Grade A, corresponding to the lowest sugar and saturated fat thresholds, will be in green and Grade D, corresponding to the highest sugar and saturated fat thresholds, will be in red.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sugar Levels	Grams of sugar per serving	After completion of data collection, an average of about 5 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Calorie Intake	Calorie intake per serving and per shopping trip (kcal)	After completion of data collection, an average of about 5 months
Purchased Beverage Quality	The proportion of Nutri-Graded C and D beverage servings purchased	After completion of data collection, an average of about 5 months
Overall Diet Quality	Overall diet quality as measured by the average Nutri-Score weighted by the number of serving size. Nutri-Score is an individual dietary index based on the British Food Standard Agency Nutrient Profiling System.	After completion of data collection, an average of about 5 months

Collaborators and Investigators

• Sponsor: Duke-NUS Graduate Medical School
• Investigators: Principal Investigator: Soye Shin, PhD, Duke-NUS Graduate Medical School

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2021
• Primary Completion (Actual): December 31, 2021
• Study Completion (Actual): January 31, 2022

Study Registration Dates

• First Submitted: August 13, 2021
• First Submitted That Met QC Criteria: August 19, 2021
• First Posted (Actual): August 24, 2021

Study Record Updates

• Last Update Posted (Actual): March 23, 2022
• Last Update Submitted That Met QC Criteria: March 21, 2022
• Last Verified: March 1, 2022

More Information

Terms related to this study

• Keywords: Diet quality; Sugar-sweetened beverages; Nutri-Grade labels; Online grocery shopping
• Other Study ID Numbers: Duke-NUS-KPFA/2020/0042

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No