nutrients Review Experimental Studies of Front-of-Package Nutrient Warning Labels on Sugar-Sweetened Beverages and Ultra-Processed Foods: A Scoping Review Lindsey Smith Taillie 1,*, Marissa G. Hall 2, Barry M. Popkin 1 , Shu Wen Ng 1 and Nandita Murukutla 3 1 Department of Nutrition, University of North Carolina at Chapel Hill, 135 Dauer Dr, Chapel Hill, NC 27599, USA;
[email protected] (B.M.P.);
[email protected] (S.W.N.) 2 Department of Health Behavior, University of North Carolina at Chapel Hill, 135 Dauer Dr, Chapel Hill, NC 27599, USA;
[email protected] 3 Vital Strategies, 100 Broadway 4th floor, New York, NY 10005, USA;
[email protected] * Correspondence:
[email protected]; Tel.: +1-312-342-9783 Received: 29 January 2020; Accepted: 18 February 2020; Published: 22 February 2020 Abstract: Policies that require front-of-package (FoP) nutrient warnings are becoming increasingly common across the globe as a strategy to discourage excess consumption of sugary drinks and ultra-processed food. However, a better understanding of the pathway through which FoP nutrient warnings work, as well as a review of how outcomes being measured in recent studies map onto this pathway, are needed in order to inform policy on the most effective FoP label design for reducing purchases of ultra-processed foods. This scoping review describes a conceptual model for how FoP nutrient warnings affect consumer behavior, examines which of these outcomes are currently being measured, and summarizes evidence from randomized controlled experiments. Twenty-two studies which experimentally tested nutrient warnings against a control label or other labeling systems were included for full-text review.