The relative ability of different front-of-pack labels to assist consumers discriminate between healthy, moderately healthy, and unhealthy foods

Highlights

• Health Star Ratings aided discrimination between foods of all levels of healthiness.

• Multiple traffic lights were only effective for larger discrepancies in healthiness.

• The Daily Intake Guide did not facilitate discrimination of foods by healthiness.

• Without front-of-pack labels, respondents could not differentiate by healthiness.

Abstract

The degree to which different front-of-pack labels (FoPLs) can assist consumers to make healthy choices seems to depend on the extent to which the FoPLs provide an interpretation of the nutrition information presented. The aim of this study was to assess the effectiveness of three FoPLs that vary by interpretive content in allowing consumers to discriminate between products of varying healthiness. Australian consumers (n = 2058) rated the perceived healthiness of mock food pack images that varied according to: nutritional profile (healthy, moderately healthy, unhealthy); FoPL (Daily Intake Guide (DIG), Multiple Traffic Lights (MTL), Health Star Rating (HSR), or control); and food type (cookies, cornflakes, pizza, yoghurt). Respondents were most accurate at differentiating unhealthy products from healthy (p < 0.001) and moderately healthy products (p = 0.015) when the HSR appeared on packs. The MTL was marginally (p = 0.052) effective at helping respondents distinguish between healthy and unhealthy products. When the DIG or no FoPL was used, however, respondents were unable to discriminate between a healthy and an unhealthy nutritional profile. Findings indicate that the HSR is more effective than other commonly used FoPLs in assisting consumers to accurately evaluate the healthiness of food products.

Introduction

The provision of front-of-pack labels (FoPLs) on prepackaged foods is a common public health intervention aimed at reducing diet-related chronic disease (Cecchini et al., 2010, Hawkes, 2010). Different FoPLs vary in how effectively they assist consumers to make healthy choices, which is likely to be related to the degree to which they provide an interpretation of the nutrient profiles of foods (Hamlin, McNeill, & Moore, 2015). The Daily Intake Guide (DIG), which states the level of select negative and positive nutrients (e.g., fat, sugar, protein) within a product in grams per serve and as a percent of an average adult’s recommended daily intake, is known as a reductive FoPL because it provides little interpretation of nutrition information. The Multiple Traffic Lights (MTL) FoPL, which use the colors red, amber and green to indicate whether negative nutrients are high, medium or low respectively, is known as an evaluative FoPL because it provides more interpretation of the nutrition information. Evidence suggests that evaluative FoPLs are more likely to lead to greater accuracy in determining relative healthiness and greater intentions to purchase healthier products than reductive FoPLs (Hawley et al., 2013, Hersey et al., 2013).

The Health Star Rating (HSR) has recently been introduced as a voluntary evaluative FoPL in Australia and New Zealand (Australian Government Department of Health, 2013). Manufacturers can choose to specify the amount of key nutrients per 100 g or per portion and include text to indicate whether nutrient levels are high or low. The key differentiating aspect of the HSR is a summary indicator (that is always present) that rates overall product healthiness from half a star to five stars. Focus group research suggests that consumers find the summary indicator in the HSR easier to interpret than nutrient-level information (both in the HSR and other FoPLs; Talati et al., 2016) However, quantitative evidence to support this suggestion is lacking. Another study recently found that across healthy and unhealthy foods, respondents were less likely to select a product if the HSR was present rather than absent (Hamlin & McNeill, 2016), although this may have been because the HSR was colored red in that study and red has been shown to create avoidance reactions to foods regardless of actual healthiness (Rohr, Kamm, Koenigstorfer, Groeppel-Klein, & Wentura, 2015). Importantly, the main effect of package design was far greater than the main effect of the HSR, suggesting that consumers were basing their choice more on other elements of the package design than the FoPL.

The aim of the present study was to quantitatively measure consumers’ perceptions of product healthiness resulting from exposure to FoPLs characterized by varying levels of interpretive content. Listed from least to most interpretive content, the three tested FoPLs were the DIG that provides only reductive nutrient-level information, the MTL with its color-coded nutrient-level interpretations and the HSR with its summary indicator and text-based nutrient-level interpretations. It was hypothesized that ratings of perceived healthiness would be more aligned with a product’s nutritional profile when the HSR or MTL was present, but not when the DIG or no FoPL was present. The interaction of these variables with demographic factors such as age, gender and socioeconomic status (SES) was also explored.