The impact of the nutri-score on food choice: A choice experiment in a Dutch supermarket

Abstract

Front-of-package (FOP) nutrition labels are placed on products to help consumers make healthy food choices. A lab-in-field experiment was conducted to test the effectiveness of two FOP labels in promoting healthy food choices among Dutch consumers, and to examine whether dieters and health conscious shoppers are more likely to use the FOP labels. In addition, it was examined whether the placement of relatively “good” FOP label scores on products might inadvertently lead to increases in serving sizes. Participants (N = 300) consisted of Dutch consumers shopping for groceries in a local supermarket. They were randomly assigned to one of three conditions (Nutri-score, Multiple Traffic Light (MTL) label, or no label control condition), presented with six different (labeled) cereals, and asked to make a choice. Next, participants were shown a product with a relatively good label score and selected their desired serving size. The results show that the Nutri-score promotes choice of the healthiest cereal. Dieting behaviour and health conscious shopping did not moderate this effect, and the labels did not affect serving size selection. Overall, the study provides evidence for the Nutri-score to promote healthy food choices among Dutch consumers.

Introduction

Obesity prevalence has increased dramatically worldwide (Arroyo-Johnson & Mincey, 2016). In an effort to promote healthy eating, several countries have now adopted front-of-package (FOP) nutrition labels that provide simplified nutritional information of a product (van der Bend & Lissner, 2019). The idea is that consumers can use FOP labels to quickly evaluate and compare the healthiness of foods and more readily choose healthier options (Cheftel, 2005; Tarabella & Voinea, 2013). The Dutch government has recently indicated its willingness to adopt the Nutri-score as new FOP label, which will be presented on products on a voluntary basis (Rijksoverheid, 2020). The Nutri-score provides a single colour-coded summary score (ranging from A to E) to indicate the overall healthiness of a product. The score is calculated using a point system in which negative points are awarded for energy density, saturated fats, simple sugars, and sodium, and positive points for the amount of fruit, vegetable, pulses, nuts, certain oils, fibers, and proteins in the product. Positive points are subtracted from the negative points to arrive at an overall healthiness score. The Nutri-score has not yet been implemented in the Netherlands; currently, it is being evaluated whether or how the algorithms underlying the Nutri-score can be harmonized with national dietary guidelines across different EU countries (Ministerie van VWS, 2020). Research has shown that the Nutri-score is well accepted by Dutch consumers (Consumentenbond, 2018), although they seem to prefer another promising labeling scheme, the Multiple Traffic Light (MTL) label, which presents the caloric value of a product as well as colour-coded levels of specific nutrients (i.e., fat, saturated fat, sugar, and salt; Consumentenbond, 2018; Egnell et al., 2019). This raises the question which of these labels would be more effective (i.e., increase understanding of, and choice for, healthier options) among Dutch consumers.

A recent meta-analysis examined the overall and relative effectiveness of different types of FOP labels (Ikonen, Sotgiu, Aydinli, & Verlegh, 2020; see also; Cecchini & Warin, 2016). It was found that while FOP labels in general help consumers to identify the healthier option, simple summary indicators such as the Nutri-score are particularly effective. However, this meta-analysis also found that the overall effects of FOP labels on healthy choices were more limited. In addition, no FOP label type appeared clearly superior in promoting healthy choice. Similarly, a recent review concluded that although FOP labels may have small effects on purchase decisions, findings have been mixed, and it remains unclear which labeling scheme is most effective (Temple, 2019). Thus, although studies seem to suggest that the Nutri-score and MTL label can have beneficial (albeit limited) effects on food choice, their relative effectiveness warrants further investigation.

Further research is also needed on whether certain groups of consumers are more likely to use FOP labels when making product choices. Several studies have examined moderating effects of certain socio-demographic characteristics, such as gender, age, or education (Egnell, Ducrot, et al., 2018; Finkelstein, Ang, Doble, Wong, & van Dam, 2019; Ikonen et al., 2020). However, it seems plausible that especially individuals who are motivated to eat healthily – such as those trying to lose weight – will be more likely to use the information provided by FOP labels. In line with this, several prior studies have shown that healthy products that carry front-of-pack nutritional information (such as a health claim) are particularly attractive for dieters (Girz, Polivy, Herman, & Lee, 2012; Lwin et al., 2014; Vyth et al., 2010) and for individuals who indicate to pay attention to nutritional information when shopping (Keller et al., 1997; Vyth et al., 2010). The fact that such individual differences are often not taken into account in prior FOP labelling studies might explain some of the mixed findings of prior studies; whether or not beneficial effects of a labeling scheme on food choice was found might have depended on the study's specific sample composition.

FOP label effects can also differ across different cultural contexts (e.g., Talati, Egnell, Hercberg, Julia, & Pettigrew, 2019), highlighting the importance to examine effects at a country-specific level. To date, only one study has examined the effectiveness of the Nutri-score in promoting healthy choices among Dutch consumers. In this study, participants received an online questionnaire in which they were presented with pictures of three products (e.g., three pizzas) and asked to indicate which one they would purchase. The task was then repeated, only this time, a FOP label (e.g., the Nutri-score or MTL label) was presented on the products. Results indicated that neither the MTL nor the Nutri-score promoted healthy choices (Egnell et al., 2019). Possibly, given that the study was conducted online (like most FOP labeling studies), external validity was limited; for example, it is well-known that in online studies, task attention can be substantially lower than in offline settings (Berinsky et al., 2014). It is also possible that due to the use of a within-subjects control group, participants had guessed the aim of the study which may have interfered with labeling effects. Thus, it seems prudent to test the relative effectiveness of the Nutri-score and MTL label in a Dutch consumer sample, taking into account these considerations.

Finally, several researchers have highlighted the possibility of counterproductive effects when labeling foods as healthy. For example, several studies have shown that when food is framed as being healthy, consumers tend to serve greater portion sizes and, as a result, consume larger amounts of food – presumably because they underestimate the caloric density of the food, feel less guilty about eating more, and/or judge the appropriate serving size to be larger (e.g., Provencher, Polivy, & Herman, 2009; Wansink & Chandon, 2006; Brown, Rollo, de Vlieger, Collins, & Bucher, 2018). To date, no studies have specifically examined whether relatively “good” scores on FOP labels would similarly result in increased serving sizes, which would (partially) compensate for any beneficial effects of FOP labels on food choice.¹ In support, a recent experiment that examined the effects of “bad” scores of FOP labels on intended serving sizes of unhealthy food (such as cheese) found that both labels resulted in lower serving sizes (Egnell, Ducrot, et al., 2018; see also; Talati et al., 2018).

The primary aim of the current study was to examine the effectiveness of the Nutri-score and MTL label in promoting healthier food choice in a Dutch consumer sample and to investigate whether certain groups of consumers (specifically, those trying to lose weight or trying to choose healthier options) are more likely to use the labels when making product choices. As a secondary objective, it was examined whether the labels would increase intended serving sizes of a product with a good label score. A lab-in-field experiment in a Dutch supermarket was conducted to investigate these questions.