Testing the Effects of Singapore's Front-of-Pack Healthier Choice Symbol Label With or Without a Physical Activity Equivalent Label

Study Overview
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Brief Summary
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Poor diets are known risk factors for chronic diseases, and in recent years, food labelling has been increasingly sought-after as a cost-effective intervention to help stem the rising trend in chronic diseases. In efforts to promote a healthy diet, the Singapore Health Promotion Board (HPB) supplements traditional nutrition labelling with the Healthier Choice Symbol (HCS), which identifies food items within a specific category of foods as healthier choices. The original logos were enhanced to include additional information focusing on particular macronutrients, taking one of two themes; it either indicates that a product contains more of a healthier ingredient, or less of a less healthy ingredient. However, to date, no published studies have assessed the role of the original and enhanced HCS logos in influencing food choices. There is a lack of scientific evidence on the role of the existing symbols in assisting consumers make healthier food purchasing decisions. There are also concerns over the unintended consequences of health claims made based on a single aspect of nutrient content, without considering other aspects. That is the goal of this effort. Specifically, the investigators propose to conduct the following: Use a three arm randomized controlled trial (RCT) and an experimental fully functional web-based grocery store to assess the causal effect of the new HCS logos on measures of diet quality either alone, or in combination with a complementary front-of-package (FOP) label: Physical Activity Equivalents (PAEs), which provides information on how long one would need to engage in a certain activity (e.g., jogging) to burn off one serving of the product. The investigators hypothesize that the greatest reduction in calories per serving (primary outcome) will occur in the HCS plus PAEs arm, followed by HCS only, and no logo control arm.

Official Title
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A Randomized Controlled Trial Testing the Effects of Singapore's Front-of-Pack Healthier Choice Symbol Label With or Without a Physical Activity Equivalent Label on Food Purchases and Measures of Diet Quality

Conditions
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Obesity, Diabetes, Diet, Healthy

Intervention / Treatment
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* Behavioral: Healthier Choice Symbol
* Behavioral: Physical Activity Equivalent label


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Singapore residents 21 years of age and above Primary grocery shopper for the household Exclusion Criteria: Not residing in Singapore Under 21 years of age Not the primary grocery shopper for the household

Ages Eligible for Study
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Minimum Age: 21 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Health Services Research
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: This will be a crossover study design with all participants exposed once to 3 shopping conditions (1xControl, 1x Arm 2 and 1x Arm 3) in random order. The total study duration for each participant is 3 weeks, with each participant spending 1 week in each shopping condition.
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: No labeling Control<br>Arm 1 was the Control condition, which did not display FOP labels on any products. | |
| Experimental: HCS-only<br>Arm 2 (termed HCS-only) displayed the HCS on eligible products, crossed referenced via the Health Promotion Board's HCS database (https://www.hpb.gov.sg/food-beverage/healthier-choice-symbol). Out of the 4,177 products available on NUSMart, 311 (7·45%) carried the HCS. This was comprised of 150 foods and 161 beverages. | Behavioral: Healthier Choice Symbol<br>* The HCS is intended to improve diet quality by signaling to consumers which products are healthier options within a specific category (e.g., which are the healthier biscuits or the healthier beverages). Manufacturers must meet category-specific criteria before a product can display the HCS and an associated tagline. The labels were displayed at the bottom of the product images.<br>|
| Experimental: HCS+PAE<br>Arm 3 displayed the HCS on eligible products as in Arm 2 and the PAE label on all products (termed HCS+PAE). PAE was calculated as the minutes required to burn off the calories of a single serving for a 73 kg person jogging at 8 km per hour. | Behavioral: Healthier Choice Symbol<br>* The HCS is intended to improve diet quality by signaling to consumers which products are healthier options within a specific category (e.g., which are the healthier biscuits or the healthier beverages). Manufacturers must meet category-specific criteria before a product can display the HCS and an associated tagline. The labels were displayed at the bottom of the product images.<br>Behavioral: Physical Activity Equivalent label<br>* For the study, we designed a simple PAE logo (Appendix Figure A1) and added a description encoded into the NUSMart user interface to ensure that participants would understand the contents of the label. Participants saw the following description whenever their cursor hovered over the PAE label: The Physical Activity Equivalent (PAE) refers to the number of minutes that a typical adult would need to jog to burn off the calories associated with one serving of the product. Previous studies have shown this labelling approach to be effective. The labels were displayed at the bottom of the product images.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in average calories per serving purchased per shopping trip | Calories per serving (kCal per serving) is calculated by dividing the total number of calories purchased in the shopping trip by the total number of servings purchased. The average calories per serving purchased (kcal per serving) is based on mean standardized serving sizes within each subcategory. | Once a week for three weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of HCS labelled products purchased (or would have been if not in control arm) per shopping trip | Calories per Shopping Trip will be calculated as the sum of all purchased products' total calories. | Once a week for three weeks | 
| Total Calories per shopping trip | Total calories purchased in kcal. | Once a week for three weeks | 
| Diet quality per shopping trip as measured by the Grocery Purchase Quality Index-2016 | Diet quality per shopping trip as measured by the Grocery Purchase Quality Index-2016 (GPQI-2016). The Grocery Purchase Quality Index-2016 (GPQI-2016) contains 11 different food components with eight components scored based on adequacy and three moderation components. We followed the standard GPQI-2016 scoring methods by mapping NUSMart's subcategories to USDA food plan categories and then to the GPQI components. Each component was scored based on the deviation of the observed expenditure share of each component and the expected expenditure share, and the scores were totaled up to generate the final GPQI-2016 score (minimum possible score = 0, maximum possible score = 75) for each participant's weekly grocery order. A higher score indicates better diet quality of the grocery basket. | Once a week for three weeks | 
| Diet quality per shopping trip as measured by weighted average Nutri-Score | We applied the standard Nutri-Score algorithm to assign a grade to each product. This algorithm assigns a score of A to E based on nutritional quality, which we recoded to 5 to 1 and then calculated an average score for each participant's weekly grocery order (minimum possible score = 0, maximum possible score = 5), weighted by the number of servings of each product. A higher score indicates better diet quality of the grocery basket. | Once a week for three weeks | 
| Sugar per serving per shopping trip | Amount of sugar (g) per serving purchased based on mean standardized serving sizes within each subcategory. | Once a week for three weeks | 
| Sodium per serving per shopping trip | Amount of sodium (mg) per serving purchased based on mean standardized serving sizes within each subcategory. | Once a week for three weeks | 
| Saturated fat per serving per shopping trip | Amount of saturated fat (g) per serving purchased based on mean standardized serving sizes within each subcategory. | Once a week for three weeks | 
| Calories per dollar spent per shopping trip | Number of calories per dollar (kcal per dollar) spent | Once a week for three weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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nutrition, front-of-pack label, calories, online grocery store, Singapore, physical activity equivalent