A randomized trial to evaluate the impact of Singapore’s forthcoming Nutri-grade front-of-pack beverage label on food and beverage purchases

BACKGROUND: The epidemic of non-communicable diseases (NCDs) is a growing concern worldwide and Singapore is no exception to this global trend. As part of measures to address this concern, the Singapore government will implement a mandatory color-coded front-of-package (FOP) nutrition label for beverages, called Nutri-Grade (NG), which will complement the existing FOP label, Healthier Choice Symbol (HCS) logos, currently displayed on select food and beverage items. NG grades beverages on a four-point scale, A (healthiest) to D (least healthy), in terms of sugar and saturated fat levels. This study aimed to evaluate the effectiveness of the NG label on nutritional quality of pre-packaged beverages using a fully functional online grocery store. METHODS: We conducted a 2-arm crossover trial involving actual purchases with 138 participants randomly exposed to: 1) Control with HCS logos displayed on qualifying items; 2) Similar to Control except that all beverages displayed the NG label. The effects of the NG label were estimated using a linear mixed-effects model that addresses correlations between repeated measures and accommodates missing data. RESULTS: We found that the NG label encouraged consumers to choose beverages with higher ratings. This led to a reduction in sugar from beverages purchased by 1.51 g [95% CI: − 2.68, − 0.34] per serving but was not effective at reducing saturated fat purchased (− 0.009 g [95% CI: − 0.22, 0.20]) per serving or improvements in overall diet quality, measured by the weighted (by the number of servings) average Nutri-Score value ranging from 1 to 5 (− 0.024 [95% CI: − 0.13, 0.08]). CONCLUSIONS: Results suggest that the Nutri-Grade label is likely to reduce sugar purchased from beverages. However, to improve overall diet quality in Singapore, additional measures will be needed. TRIAL REGISTRATION: This trial was registered on ClinicalTrials.gov under the identifier: NCT05018026 on 24th August 2021. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12966-023-01422-4.