Impact of color-coded and warning nutrition labelling schemes: A systematic review and network meta-analysis

Abstract

Background Suboptimal diets are a leading risk factor for death and disability. Nutrition labelling is a potential method to encourage consumers to improve dietary behaviour. This systematic review and network meta-analysis (NMA) summarises evidence on the impact of colour-coded interpretive labels and warning labels on changing consumers’ purchasing behaviour. Methods and findings We conducted a literature review of peer-reviewed articles published between 1 January 1990 and 24 May 2021 in PubMed, Embase via Ovid, Cochrane Central Register of Controlled Trials, and SCOPUS. Randomised controlled trials (RCTs) and quasi-experimental studies were included for the primary outcomes (measures of changes in consumers’ purchasing and consuming behaviour). A frequentist NMA method was applied to pool the results. A total of 156 studies (including 101 RCTs and 55 non-RCTs) nested in 138 articles were incorporated into the systematic review, of which 134 studies in 120 articles were eligible for meta-analysis. We found that the traffic light labelling system (TLS), nutrient warning (NW), and health warning (HW) were associated with an increased probability of selecting more healthful products (odds ratios [ORs] and 95% confidence intervals [CIs]: TLS, 1.5 [1.2, 1.87]; NW, 3.61 [2.82, 4.63]; HW, 1.65 [1.32, 2.06]). Nutri-Score (NS) and warning labels appeared effective in reducing consumers’ probability of selecting less healthful products (NS, 0.66 [0.53, 0.82]; NW,0.65 [0.54, 0.77]; HW,0.64 [0.53, 0.76]). NS and NW were associated with an increased overall healthfulness (healthfulness ratings of products purchased using models such as FSAm-NPS/HCSP) by 7.9% and 26%, respectively. TLS, NS, and NW were associated with a reduced energy (total energy: TLS, −6.5%; NS, −6%; NW, −12.9%; energy per 100 g/ml: TLS, −3%; NS, −3.5%; NW, −3.8%), sodium (total sodium/salt: TLS, −6.4%; sodium/salt per 100 g/ml: NS: −7.8%), fat (total fat: NS, −15.7%; fat per 100 g/ml: TLS: −2.6%; NS: −3.2%), and total saturated fat (TLS, −12.9%; NS: −17.1%; NW: −16.3%) content of purchases. The impact of TLS, NS, and NW on purchasing behaviour could be explained by improved understanding of the nutrition information, which further elicits negative perception towards unhealthful products or positive attitudes towards healthful foods. Comparisons across label types suggested that colour-coded labels performed better in nudging consumers towards the purchase of more healthful products (NS versus NW: 1.51 [1.08, 2.11]), while warning labels have the advantage in discouraging unhealthful purchasing behaviour (NW versus TLS: 0.81 [0.67, 0.98]; HW versus TLS: 0.8 [0.63, 1]). Study limitations included high heterogeneity and inconsistency in the comparisons across different label types, limited number of real-world studies (95% were laboratory studies), and lack of long-term impact assessments. Conclusions Our systematic review provided comprehensive evidence for the impact of colour-coded labels and warnings in nudging consumers’ purchasing behaviour towards more healthful products and the underlying psychological mechanism of behavioural change. Each type of label had different attributes, which should be taken into consideration when making front-of-package nutrition labelling (FOPL) policies according to local contexts. Our study supported mandatory front-of-pack labelling policies in directing consumers’ choice and encouraging the food industry to reformulate their products. Protocol registry PROSPERO (CRD42020161877).

Evaluation of Nutri-Score in Relation to Dietary Guidelines and Food Reformulation in The Netherlands

“…It must also be noted that many other aspects influence dietary choices, such as individual preferences and social, economic and environmental factors [24]. Previous online studies have indicated that Nutri-Score can help consumers to rank products in a similar product group, from healthy to less healthy options [8,25], and to choose more healthful products in an experimental setting [26]. Additional research is, however, needed on actual purchasing behaviour in a real-life setting [26], and the effect of Nutri-Score on the consumers' eating pattern [25].…”

Analysis of Content, Social Networks, and Sentiment of Front-of-Pack Nutrition Labeling in the European Union on Twitter

“…Such a system is considered as an important tool to tackle obesity and NCDs as nutrition information should not be based solely on the less efficient ingredient list of prepackaged foods. Whatever FOPL system is implemented ( 67 ), it is important to ensure that it is an integral part of the response to obesity and disease is important. Our results made it clear that discussions about FOPL on Twitter are limited to a narrow circle; therefore, consumers' education on FOPL should be emphasized, making people aware of existing and upcoming FOPL systems ( 68 ).…”

Polish Consumers’ Understanding of Different Front-of-Package Food Labels: A Randomized Experiment

“…The wide variety of FoPL (developed by public or private entities) used around the world can be grouped into two main kinds: those that display numeric data on specific nutrient content (i.e., nutrient-specific labels) and those that synthesize information on ingredient and/or nutrient content into a graphic and/or color-coded logo (i.e., summary labels) [ 9 ]. Generally, salient, color-coded and easily comprehensible FoPL have been shown to be effective in steering consumers towards selecting healthier food/beverage options and also in urging manufacturers to engage in product reformulation [ 6 , 8 , 10 ]. Recently, the European Commission underscored the need to implement a uniform and mandatory FoPL at the EU level [ 8 ].…”