Healthy labels, healthy portions? The impact of favorable nutri-scores on consumers' portion size selection and food intake

While front-of-pack labels have been found to positively impact purchase intentions and food choices, their potential negative impact on portion sizes and food intake remains understudied. We focused on the Nutri-Score, a front-of-pack label that summarizes the nutritional quality of foods with a five color-letter combination. We tested whether favorable Nutri-Scores (A and B) increased consumers' portion sizes and their actual food intake. In five online experiments, participants were presented with six portion size photographs and an option to not consume for four to twelve products per study. In two lab experiments, we measured the weight of two foods consumed on a single occasion. The results do not support our main proposition that the presence of favorable Nutri-Scores, compared to the absence of Nutri-Scores, would lead to larger selected portion sizes and an increased food intake. Neither did the results support an indirect effect of favorable Nutri-Scores on portion sizes or food intake via (1) perceptions of appropriate portion sizes, (2) the use of product healthiness as a justification cue, or (3) reduced guilt feelings. No support was found for perceived product healthiness as a moderator of the effects. These research findings mean good news, as they suggest that promoting healthier options through favorable Nutri-Scores does not inadvertently lead to larger portions or food intake. This has important implications for policy makers, retailers, and manufacturers.