Nutrition labels on packages likely to cut sugary drink consumption

Singaporeans are expected to drink a lot fewer sugar-sweetened beverages following the implementation of a front-of-pack nutrition label, named Nutri-Grade.

In a two-arm crossover trial that involved actual purchases from a fully functional online grocery store, Nutri-Grade labels facilitated a shift toward buying healthier beverages. This translated to a 1.51-g (95 percent confidence interval [CI], –2.68 to –0.34) reduction in sugar from beverages purchased per serving (p=0.012). [Int J Behav Nutr Phys Act 2023;20:18]

However, the label was less effective at reducing saturated fat purchased per serving (–0.009 g, 95 percent CI, –0.22 to 0.20) or calories purchased per serving (−3.4 kcal, 95 percent CI, − 11.9 to 5.1), as well as at improving overall diet quality (measured by the weighted average Nutri-Score value ranging from 1 to 5; –0.024, 95 percent CI, –0.13 to 0.08).

“The sugar reduction is small but could have a meaningful effect over time given that Singaporeans consume an average of 33 g of sugar from beverages daily,” the investigators pointed out. [https://www.moh.gov.sg/news-highlights/details/public-consultation-on-measures-to-reduce-sugar-intake-from-pre-packaged-sugar-sweetened-beverages; https://hpb.gov.sg/article/national-nutrition-survey-2018-shows-gradual-improvements-in-singaporeans-dietary-habits]

Nutri-Grade is a grading system that assigns each beverage a letter grade based on their sugar and saturated fat content—the two primary substances of concern for beverages. The grades range from A (healthiest) to D (least healthy) according to sugar thresholds per 100 ml. Beverages such as full cream and flavoured milks may be graded lower (but not higher) according to saturated fat thresholds per 100 ml. Nutri-Grade labels are required only for Grades C and D beverages.

“Our findings about the Nutri-Grade label’s effectiveness are consistent with the evidence on the impact of color-coded graded labels,” they noted.

“Although in the front-of-package labelling literature nutrient-specific outcomes were less commonly measured than purchasing intentions and behaviour, the Nutri-Grade’s effect on sugar reduction from beverages purchased is slightly larger than the average effect size of other front-of-package labels on sugar reduction (0.33 g per 100 g for beverages) reported by a review article,” the investigators said, adding that comparisons should be made with caution given the heterogeneity in sample and study designs. [PLoS Med 2021;18:e1003765; Obes Rev 2016;17:201-210; J Hum Nutr Diet 2020;33:518-537]

On the other hand, why the Nutri-Grade label fell short at reducing saturated fat purchased from beverages despite it being a target nutrient of the NG algorithm may have several possible explanations.

“First, the underlying Nutri-Grade algorithm largely focuses on sugar. Beverages with high sugar content receive Nutri-Grade C or D grades even if they are low in saturated fat. This means that consumers switching out of these beverages toward healthier products could actually increase saturated fat intake, whereas the converse is not true,” the investigators pointed out.

“Second, most beverages purchased in our study and in reality do not contain saturated fat, or contain only modest quantities, thus the ability to influence this nutrient through labelling policy is limited. Finally, beverages containing saturated fat such as milk could be perceived as less discretionary, therefore they may be less willing to give up these purchases due to new information on their health content,” they added.

The study included 138 participants (mean age 43 years, 69 percent women, average body mass index 24 kg/m²), with 269 unique purchases for analysis. Most participants (78 percent) had received at least a university degree, while 36 percent of participants had household monthly income of at least SGD 10,000.

Implemented in December 2022, the Nutri-Grade labelling complement the existing positive Healthier Choice Symbol (HCS) logos displayed on selected food and beverage items. There are currently more than 4,000 products showing one of 30 HCS logos, spanning across over 100 food categories.

“[B]everages only accounted for a small proportion of products purchased [in the study], and we found no evidence that healthier beverage purchases led consumers to substitute toward less healthy foods,” according to the investigators. “Given Singapore’s goal to reduce the incidence of diabetes and other noncommunicable diseases, these results suggest that additional policies will be needed.”