Which front-of-pack nutritional label (FOPNL) is most effective in promoting healthier dietary choices? An...

Mandatory interpretative front-of-pack nutrition labels (FOPNLs) are yet to be adopted in Indonesia. This study compares Indonesians' objective understanding of five FOPNLs and explores perceptions on four interpretative labels.

A randomised experiment was conducted in 4039 participants aged 16-78 years. Participants were assigned to view food products with one of five FOPNLs: Guideline Daily Amounts, Nutri-Score, multiple traffic light (MTL), warning labels (WL) or health star rating (HSR). Objective understanding was compared pre-label and post-label exposure by correctly ranking products by healthiness (Outcome 1) and identifying the healthiest (Outcome 2) and least healthy products (Outcome 3) using logistic mixed models. Healthy purchase intention post-label exposure (Outcome 4) was compared using logistic models. Perceptions of the four interpretative labels were explored.

All FOPNLs improved Outcomes 1, 2 and 3. WL and MTL performed better across all three outcomes, with no significant differences between them. Exposure to WL led to improvements of 16.3% points (95% CI 13.5 to 19.0), 9.5% points (95% CI 6.7 to 12.3) and 14.5% points (95% CI 11.3 to 17.7) for Outcomes 1, 2 and 3, respectively. MTL led to increases of 13.9% points (95% CI 11.2 to 16.6), 10.4% points (95% CI 7.4 to 13.4) and 16.8% points (95% CI 13.5 to 20.0), respectively. Proportion of participants intending to purchase the healthiest products (Outcome 4) was highest for MTL (39.6%, 95% CI 36.3 to 43.0), HSR (38.9%, 95% CI 35.5 to 42.2) and WL (35.6%, 95% CI 32.3 to 38.9), with no significant differences between them. Compared with WL and HSR, MTL was perceived as the most liked, useful, helpful and easy to identify.

MTL and WL significantly improved participants' understanding of products' nutritional quality and promoted healthier food choices. MTL may offer the best balance between effectiveness and user acceptability. These findings can inform national FOPNL policy revisions and broader efforts to improve food environments.