In this study, labels with the MTL+caloric intake and the Choices symbol were most effective for participants in determining which of 2 products was healthier; the TL+SNL labels were the least effective. In 3 instances the Choices group outperformed the MTL and MTL+caloric intake groups in comparing 2 products. In 2 of these instances, the TLs were the same for the products being compared, but neither product had a Choices symbol. In another instance, the healthier product had a Choices symbol and the comparison product did not; however, for those in the TL groups, the healthier food had a red light for saturated fat while its comparison had no red lights. This highlights a potential limitation of the MTL’s focus on individual nutrients, because consumers may be unduly swayed by a red light when the product as a whole is healthier than other products in that category. In addition, when products have the same pattern of lights, consumers understandably have trouble identifying the healthier food. It is possible that the inclusion of nutrient grams on the label would correct this problem, but the additional information may make the overall label more confusing. In contrast, the Choices labeling system made it more difficult for individuals to identify the healthier of 2 generally unhealthy products because the symbol appeared only on products meeting a certain nutrition threshold. Such a labeling scheme might cause consumers to miss a smaller but potentially meaningful shift to healthier products. These findings suggest that both the Choices and MTL+caloric intake labels have limitations but that overall they perform similarly in educating the consumer.
In estimating nutrient amounts, the TL labels strongly outperformed the Choices symbol, which does not provide specific nutrient information. However, the Choices symbol was more effective than no label for estimating saturated fat, sodium, and calories. The performance of the TL groups on the quizzes suggests that the “high, medium, low” text in combination with the traffic light color-coding scheme was effective at conveying nutrient information. Although the different TL symbols led participants to rate unhealthy products as less healthy, they did not negatively influence taste perceptions. However, intention to purchase the products was not influenced by any of the labels, suggesting that FOP labels in general might have limited influence on behavior.
This study has several limitations. Our participants were a convenience sample that responded to an advertisement for a food study and, thus, may have been more educated about nutrition than the general population. In addition, the sample was predominantly white and of a moderate-to-high socioeconomic status (SES). The more complex MTL symbol may have been easier for this better educated sample to understand than for a lower literacy group, which might perform better with a simpler label system. However, a study conducted in the United Kingdom found that labeling the TL symbols with the words high, medium, and low improved understanding among low SES participants (4
). Although middle-aged women comprised a large proportion of our study sample, research suggests that 64% of US consumers doing the grocery shopping are women who are, on average, 47 years old (19
). In addition, half of participants were overweight or obese and reported a desire to lose weight, suggesting that we studied a group that comprised a target audience for FOP labels. Although we tested a range of common food and beverage products, we did not assess whether participants usually purchase these products. Also, the presentation of products was not randomized, which may have introduced effects that influenced perceptions of different products based on order and label type. Finally, we examined label comprehension but did not assess whether the labels affected actual rather than intended purchasing patterns or consumption.
This is the first study of US consumers to compare the Choices logo with different, untested versions of the MTL label. Putting the recommended daily calories on a label could help place a product’s nutritional value in context, making it easier to identify healthier products. Participants in European focus groups preferred FOP labels that included daily calorie reference values for adults (17
). Research on restaurant menu labeling has also shown that including recommended daily calories prevented greater calorie intake after a meal (20
). Taken together, these findings suggest that such information on an FOP label could be useful, but one concern is that a single recommended number of calories is not suitable for everyone. However, 2,000 kilocalories is currently used as the basis for percent daily value nutrient calculations, which appear on the Nutrition Facts Panel. The findings from our study have public health implications given the controversy surrounding the industry’s release of Facts Up Front label (21
) and recommendations made by the IOM for an interpretive, ordinal symbol that would indicate the nutritional value of a product based on amounts of saturated fat, trans fat, sodium, and sugar (8
). The first step in selecting an FOP labeling system is to determine whether a label can be easily understood and used to estimate a product’s nutrition value. The results of our study suggest that an MTL+caloric intake label system is an easy-to-understand system that can help consumers identify healthier products and evaluate the nutrition composition of foods. In addition, our results caution against a more simplified approach to TL labeling that would only highlight specific nutrients to limit in certain food categories and suggest that the MTL+caloric intake label should be part of the national conversation about FOP labeling systems. An MTL scheme in a cafeteria setting has been found to reduce purchases of “red” products and increase purchases of “green” products, suggesting the same might be true for packaged foods, although the cafeteria’s labeling approach provided a color rating of the foods and beverages overall rather than different colors rating different nutrients in the foods and beverages (22
). A next step in decision making about FOP labeling is to conduct research that compares multiple systems, such as the Facts Up Front label, the proposed IOM symbol, the Choices system, and an MTL+caloric intake label and to test these labels in diverse populations.