Influence of sugar label formats on consumer understanding and amount of sugar in food choices: a systematic review and meta-analyses

Context: Reducing population intakes of sugar has become a focus of many national and international public health policies. Packaged foods and beverages are key contributors to sugar intakes, and food labels can be an effective tool to reduce sugar consumption. Objective: The aim of this systematic review was to examine the influence of sugar label formats on 2 outcomes: consumers' understanding of sugar information, and the amount of sugar in consumers' food choices. Data Sources: Scopus, Web of Science, PubMed, CAB Abstracts, SciELO, and the Cochrane Library databases were searched up until February 4, 2020. Study Selection: Randomized experiments or quasi-experiments were included if they investigated the influence of sugar label formats on consumers' understanding of sugar information or on the amount of sugar in consumers' food choices. Data Extraction: Data were extracted independently by 2 authors. Mean differences (MDs), standardized mean differences (SMDs), and odds ratios (ORs) plus 95%CIs were used to describe between-group differences for intervention label formats using random-effects models. Results: Twenty-three studies, which examined 39 comparisons, were included. Label formats using " high in sugar" interpretative texts (traffic light labels [MD 41.6; 95%CI 37.9-45.4] and warning signs [OR 1.33; 95%CI 1.0-1.78]) were most effective in increasing consumers' understanding of the sugar content in packaged foods. Health warning messages (SMD -0.32; 95%CI -0.43 to -0.22), graphical depictions of sugar content in teaspoons (SMD -0.32; 95%CI -0.48 to -0.17), and warning signs (SMD -0.24; 95%CI -0.35 to -0.13) were most effective for influencing consumers to choose products with lower sugar content. Conclusions: Formats that provide an interpretation of sugar information, particularly those indicating if a product is high in sugar, were more helpful than only numerical information for improving consumer understanding and promoting food choices with less sugar.