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.

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

We will make de-identified data used in the manuscript available to editors upon request either before or after publication for checking.

10 years after study completion

Reasonable request

Using a within-person crossover design, participants were randomly assigned to one of six intervention sequences, which included the order of the three shops and when the actual purchase would take place, via random permuted blocks of size three with equal allocation for the six sequences (see Appendix Table A1) by a computer program. Participants were blinded to intervention allocation, which was allocated via the NUSMart system. Allocation results were recorded within NUSMart and all investigators, including the data analyst, were blinded to group allocation.