Warning Labels for Nonnutritive Sweeteners: A Randomized Controlled Trial with Chilean Parents

In Chile, added sugar warning labels prompted product reformulation with nonnutritive sweeteners (NNS). Some countries have since adopted NNS labels to discourage this industry response, but evidence of their effects on consumer behavior is limited.

This study aimed to examine the impact of 2 types of NNS labels on Chilean parents' NNS-containing product identification, product choices for their children, and product perceptions.

In 2025, 3523 Chilean parents (children age 2-14 y) were randomly assigned to either no NNS label (control), a child-focused NNS warning ("CONTAINS NON-NUTRITIVE SWEETENERS, AVOID CONSUMPTION AMONG CHILDREN"), or an NNS disclosure ("CONTAINS NON-NUTRITIVE SWEETENERS"). Participants viewed sets of 4 products (one without added sweeteners and others with sugar, NNS, or both) and identified NNS-containing products, selected one product for their child, and, afterward, recalled labels seen. Next, participants viewed NNS-containing products and rated labels' perceived message effectiveness (PME), products' perceived healthfulness, and intentions to limit children's NNS intake. Average differential effects (ADEs) are reported in percentage points (pp) or 1 to 5 scales.

Both the child-focused NNS warning and NNS disclosure led to higher correct identification of NNS-containing products (ADE = 67 pp; ADE = 69 pp, both P < 0.001), lower selection of NNS-containing products (ADE range: -22 pp to -35 pp; ADE range: -22, -33 pp, all P < 0.001), and higher selection of products without added sweeteners (ADE range: 20-35 pp, ADE range: 22-31 pp, all P < 0.001) than control, respectively. Neither NNS label increased selection of sugar-sweetened products. NNS label recall was 63% for the child-focused NNS warning, and 84% for the NNS disclosure (P < 0.001). Both the child-focused NNS warning and NNS disclosure led to higher PME (ADE = 1.53; ADE = 0.92, both P < 0.001), lower product healthfulness perceptions (ADE = 1.43; ADE = 0.81, both P < 0.001), and higher intentions to limit children's NNS intake (ADE = 0.66; ADE = 0.17, both P < 0.001) than control, respectively.

Both NNS labels improved parents' NNS-containing product identification and encouraged choice of products without added sugar or NNS for their children.This trial was registered at the clinicaltrials.gov as NCT06842693. https://clinicaltrials.gov/study/NCT06842693.