Are nutritional warnings more efficient than claims in shaping consumers’ healthfulness perception?

Nutritional warnings highlighting high content of nutrients associated with non-communicable diseases have been recently proposed as a tool to facilitate the identification of unhealthful products. However, several different cues raising positive healthful associations are usually included on food packages, which can reduce the effectiveness of nutritional warnings. This study aimed to evaluate the effect of nutritional warnings and claims on the perceived healthfulness of four product categories, frequently consumed in Brazil: yogurt, juice, bread and crackers. For each category, eight packages were designed following a full-factorial experimental design with three two-level factors: two types of claims (present vs. absent) and nutritional warnings highlighting high content of saturated fat, sugar and/or sodium (present vs. absent). A total of 820 adults participated in an online survey. They were randomly divided into four groups, each of which evaluated the packages of one product category. For each package, participants were asked to rate their perceived healthfulness using a 7-point scale (1: not healthy at all; 7: very healthy). Data were analyzed using ANOVA considering main effects and interactions. Results showed that although claims had a significant and positive effect on the perceived healthfulness of all categories, nutritional warnings had the largest relative importance and significantly decreased perceived healthfulness. Participants who were more willing to compromise pleasure for health tended to give more relative importance to the warnings. Results suggest that nutritional warning could facilitate the identification of products with unfavorable nutrient profile and can contribute to override the positive healthful associations generated by claims.