Impact of nutrient warning labels on choice of ultra-processed food and drinks high in sugar, sodium, and saturated fat in Colombia: A randomized controlled trial

OBJECTIVE: This study assessed nutrient warnings’ impact on product selection and identification of food products high in nutrients of concern in Colombia. METHODS: In an online experiment (October 2020), 8,061 Colombians were randomized to a nutrient warning, guideline daily amounts (GDA), Nutri-Score, or no-label condition. They viewed two fruit drinks labeled according to their condition, one high in sugar and one not, and completed selection tasks. Next, they assessed four products high in sugar, sodium, and/or saturated fat (“high in” product). Finally, they selected which label would most discourage them from consuming a “high in” product. RESULTS: The nutrient warning performed better on most outcomes. Twenty percent of participants exposed to the nutrient warning would purchase the high-sugar fruit drink compared to GDA (24%, p<0.01), Nutri-Score (33%, p<0.001), and no label (29%, p<0.001). GDA performed slightly better than the nutrient warning in identifying the high-sugar fruit drink (91% vs 88%, p<0.001). The nutrient warning best helped participants correctly identify other “high in” products (75% vs. 23% no-label, 26% Nutri-Score, and 43% GDA, all p<0.001) and had the highest perceived message effectiveness (3.86 on 5-point scale vs. 2.97 GDA and 2.70 Nutri-Score, both p<0.001) and lowest likelihood of purchasing “high in” products (2.58 on 5-point scale vs. 3.23 GDA, 3.49 Nutri-Score, and 3.51 no label, all p<0.001). The nutrient warning most discouraged participants from wanting to consume “high in” products. CONCLUSIONS: Nutrient warnings are a promising policy to help consumers identify and discourage consumption of products high in nutrients of concern. TRIAL REGISTRATION: Trial Registration: NCT04567004.