of a food in a credible, distinctive, standardized, and easy-to-read format at the point of purchase, the NFP was anticipated to help consumers choose healthier and more nutritious diets (Guthrie et al., 1995).
The committee identified several studies suggesting a correlation between reading the NFP and engaging in desired behaviors. Kreuter et al. (1997), for example, showed that label readers have diets that are higher in fruit, vegetables, and fiber and lower in fat compared to non-label readers. Moreover, among label readers, those with lower fat diets report looking for fat information more often than those with higher fat diets. Similarly, those with higher fiber diets report looking for fiber information more often than those with lower fiber diets. Similar results have been reported by other studies (Kim et al., 2000; Lin and Lee, 2003; Macon et al., 2004; Satia et al., 2005; Neuhauser et al., 2007). It has also been shown that label users have diets that are lower in cholesterol relative to non-users (Guthrie et al., 1995). In a review of existing evidence, Kim et al. (2000) concluded that food labels are indeed useful tools for individuals to make healthier food choices, resulting in better health outcomes. The committee noted, however, that the studies employed correlative data, which cannot be used to demonstrate a cause-and-effect relationship between label use and food intake. In particular, because the studies did not account for selection bias, unobserved individual difference variables might have affected both label use and food intake. For example, using a quasi-experimental approach to control for unobserved selection effects, Variyam (2008) found that label use has only a modest association with diet quality. In contrast to Kim et al. (2000), this study found no evidence that label use is associated with a lower intake of total fat, saturated fat, or cholesterol.
The NFP provides a lot of detailed nutrition information that is likely to be crucial for individuals with dietary restrictions due to health conditions such as diabetes, hypertension, heart disease, etc. In fact, label readers frequently reported using nutrition labels for the purposes of avoiding certain nutrients and assessing the nutrition profile (Cowburn and Stockley, 2005). More generally, research on nutrition labeling showed that consumers report high levels of label use. However, studies that employed verbal protocols (as opposed to self-reports) showed that consumers simply look at the NFP without processing the information (Higginson et al., 2002; Cowburn and Stockley, 2005).
A necessary precondition for the NFP’s effectiveness is that consumers use and comprehend the information on food labels. Evidence reviewed by the committee, however, revealed that actual label use is much less than what is reported, and that consumers are often confused by the information on the food label and have difficulty understanding serving sizes (Cowburn and Stockley, 2005). Systematic reviews of studies conducted in the European Union (Grunert and Wills, 2007; Wills et al., 2009) and in Australia and New Zealand (Mhurchu and Gorton, 2007) reached the same conclusions.
Taken together, these studies suggest that consumers may have difficulty understanding the role of various nutrients and may not interpret the information from the perspective of how nutrients in foods may impact their daily diet. The literature offers a number of reasons for why nutrition labels are not used by consumers, including lack of time (Barreiro-Hurle et al., 2010), difficulty with the presentation of information, and lack of understanding of food label information (Cowburn and Stockley, 2005). In addition, consumers may not understand which nutrients are important, attending solely to fat or calorie information (Higginson et al., 2002). A study by Cowburn and Stockley (2005) indicated that consumers use numerical information on labels to perform simple calculations, but their ability to accurately interpret the label declines as the complexity of the task increases, especially consumers with lower levels of educational attainment.
Nutrition labeling alone is likely to offer limited success as a strategy to improve the population’s dietary health. Poor nutrition knowledge may reduce the ability of some consumers to interpret and use the nutrition information provided. When the NLEA was implemented, the federal government, along with other public- and private-sector groups, initiated a major multi-year education campaign to help consumers use the new label (Kulakow, 1995). The goal was to educate consumers about the availability of nutrition information on the food label and about the importance of using that information to maintain healthy dietary practices. However, the campaign stopped after the initial years, and nutrition labeling efforts have not been supplemented by other education strategies, which has resulted in adverse consequences for consumer use of the NFP.