Food product health warnings promote dietary self-control through reductions in neural signals indexing food cue reactivity

The Time-Course of Food Representation in the Human Brain

Humans make decisions about food every day. The visual system provides important information that forms a basis for these food decisions. Although previous research has focused on visual object and category representations in the brain, it is still unclear how visually presented food is encoded by the brain. Here, we investigate the time-course of food representations in the brain. We used time-resolved multivariate analyses of electroencephalography (EEG) data, obtained from human participants (both sexes), to determine which food features are represented in the brain and whether focused attention is needed for this. We recorded EEG while participants engaged in two different tasks. In one task, the stimuli were task relevant, whereas in the other task, the stimuli were not task relevant. Our findings indicate that the brain can differentiate between food and nonfood items from ∼112 ms after the stimulus onset. The neural signal at later latencies contained information about food naturalness, how much the food was transformed, as well as the perceived caloric content. This information was present regardless of the task. Information about whether food is immediately ready to eat, however, was only present when the food was task relevant and presented at a slow presentation rate. Furthermore, the recorded brain activity correlated with the behavioral responses in an odd-item-out task. The fast representation of these food features, along with the finding that this information is used to guide food categorization decision-making, suggests that these features are important dimensions along which the representation of foods is organized.

Effects of immediate and distant health consequences: different types of health warning messages on sweets affect the purchase probability

BACKGROUND

Several health control policies have been discussed as a regulatory approach to tackle the increasing prevalence of obesity and other health risks related to sugar consumption. Health warnings, like the ones used in tobacco control worldwide, are one of the most promising approaches. However, in the case of health warning messages for food products, it is much more complicated and involves much more consumer involvement than tobacco guidance. Therefore, it is important to better understand the efficacy, evaluation, and reactance of health warning labels in the food sector regarding consumers' behavior, persuasion, and perceptions. The aim of this study was to examine how different types (design and message) of health warning messages in combination with graphical applications affect consumer behavior.

METHODS

In a 3 × 3 × 3 symmetrical design, 1,040 German participants completed an online discrete choice experiment including various text-only and image-and-text health warning labels on sweets. An accompanying questionnaire assessed socio-demographic variables as well as psychometric scales to understand the relationship between fear, control, reactance, and shocking/inhibiting/mediating health-related warnings.

RESULTS

Our results suggest that especially emotional graphical images combined with text health warning labels might be more influential. The health effects of immediate (caries) and more distant health consequences (diabetes/obesity) differ in their impact. Further, results show that especially when consumers engage in a danger control process for overweight, warning messages have a negative impact on their choices.

CONCLUSION

Hence, warning labels on sweets can potentially be a decisive factor when communicating health threats related to excessive sugar consumption. In the context of a targeted health policy, we see the need for further research, especially concerning the perception and understanding of noncommunicable diseases (NCDs) in the population.

Impact of textual warnings on emotional brain responses to ultra-processed food products

Background and objectives

Ultra-processed food products (UPF) have been associated with numerous non-communicable diseases. Despite this, the addictive nature of UPF, and the aggressive marketing strategies used to promote them, has created a strong emotional connection between UPF and consumers, and supports their increasing UPF global consumption. In view of the emotional link that consumers often have with UPF, modulating emotional reactions to UPF (by using strategies such as textual warnings) is important in changing consumers' behavior. Since emotions are better understood by assessing individuals' implicit reactions, we conducted an electroencephalographic study applying the event-related potential technique to investigate whether textual warnings were able to modulate the brain responses to UPF stimuli.

Materials and methods

Twenty-six participants (19 women) viewed pictures of UPF preceded by a warning sentence about the health risks of consuming UPF or a control sentence while the electroencephalogram was recorded. In addition, the participants rated the picture in respect of pleasantness, arousal, and intention to consume. As emotions are associated with motivational circuits in the brain, we focused on a well-known event-related potential brain marker of the motivational relevance associated with emotional stimuli, namely late positive potential (LPP).

Results

The late positive potential amplitude was larger for pictures depicting UPF under the warning condition compared to the control condition, a result that was accompanied by lower pleasantness ratings during the warning condition (compared to the control).

Conclusion

Textual warnings about the negative health consequences of consuming UPF changed the emotional responses toward UPF, possibly increasing the motivation to avoid UPF. These results shed new light on the impact of textual warnings on UPF-evoked emotions.

Effect of health warning labels on motivation towards energy-dense snack foods: Two experimental studies

Health warning labels (HWLs) show promise in reducing motivation towards energy-dense snack foods. Understanding the underlying mechanisms could optimise their effectiveness. In two experimental studies in general population samples (Study 1 n = 90; Study 2 n = 1382), we compared the effects of HWLs and irrelevant aversive labels (IALs) on implicit (approach) motivation towards unhealthy snacks, using an approach-avoidance task (Study 1), and a manikin task (Study 2). We also assessed explicit motivation towards unhealthy snacks using food selection tasks. We examined whether labelling effects on motivation arose from the creation of outcome-dependent associations between the food and its health consequences or from simple, non-specific aversive associations. Both label types reduced motivation towards snack foods but only when the label was physically present. HWLs and IALs showed similar effects on implicit motivation, although HWLs reduced explicit motivation more than IALs. Thus, aversive HWLs appear to act both through low level associative mechanisms affecting implicit motivation, and by additionally emphasizing explicit causal links to health outcomes thereby affecting explicitly motivated choice behaviours.

Decoding explicit and implicit representations of health and taste attributes of foods in the human brain

Obesity has become a significant problem word-wide and is strongly linked to poor food choices. Even in healthy individuals, taste perceptions often drive dietary decisions more strongly than healthiness. This study tested whether health and taste representations can be directly decoded from brain activity, both when explicitly considered, and when implicitly processed for decision-making. We used multivariate support vector regression for event-related potentials (as measured by the electroencephalogram) to estimate a regression model predicting ratings of tastiness and healthiness for each participant, based on their neural activity occurring in the first second of food cue processing. In Experiment 1, 37 healthy participants viewed images of various foods and explicitly rated their tastiness and healthiness. In Experiment 2, 89 healthy participants completed a similar rating task, followed by an additional experimental phase, in which they indicated their desire to consume snack foods with no explicit instruction to consider tastiness or healthiness. In Experiment 1 both attributes could be decoded, with taste information being available earlier than health. In Experiment 2, both dimensions were also decodable, and their significant decoding preceded the decoding of decisions (i.e., desire to consume the food). However, in Experiment 2, health representations were decodable earlier than taste representations. These results suggest that health information is activated in the brain during the early stages of dietary decisions, which is promising for designing obesity interventions aimed at quickly activating health awareness.

Effects of pairing health warning labels with energy-dense snack foods on food choice and attitudes: Online experimental study

BACKGROUND

There is limited evidence concerning the potential effectiveness of health warning labels (HWLs) using images and text to depict possible negative health consequences of consumption, for reducing selection of energy-dense snack foods. Furthermore, the underlying mechanisms have received little attention; particularly effects on implicit attitudes, which previous work has shown may mediate the effect of aversive images on food choice.

AIM

To assess the impact of pairing image- and text-based HWLs with energy-dense snack foods on a) the selection of, and b) implicit and explicit attitudes towards, those foods.

METHODS

Online experimental study with a representative UK sample (n = 1185), using a 2(Image/No Image) x 2(Text/No Text) factorial between-subjects design. Participants were randomised to one of four study arms, viewing snack food images paired with either: image-only HWLs, text-only HWLs, image-and-text HWLs, or no HWLs (control). HWLs concerned various negative health consequences of excess energy intake, such as heart disease and type 2 diabetes. The primary outcome was hypothetical food choice (energy-dense snack foods versus fruit), assessed post-intervention. Secondary outcomes were implicit and explicit attitudes.

RESULTS

Neither food choice nor explicit attitudes were changed significantly by any type of HWL. Implicit attitudes towards energy-dense snack foods were more negative after exposure to text-only or image-and-text HWLs. Both implicit and explicit attitudes predicted unique variance in food choice.

CONCLUSIONS

This study suggests that short-term repeated exposure to HWLs paired with energy-dense snack foods may not consistently alter food choices, but can change implicit attitudes associated with food choices. Further laboratory and field studies are needed to more definitively assess the impact of HWLs on food selection and consumption in applied contexts and over time, as well as delineate underlying mechanisms.

General and specific graphic health warning labels reduce willingness to consume sugar-sweetened beverages

Sugar-sweetened beverage (SSB) consumption is associated with obesity and other severe negative health consequences. The present study examined the effectiveness of two types of health warning labels (HWLs) in modulating dietary choices for SSBs: specific HWLs, presenting health consequences associated with consuming SSBs, and general HWLs, presenting health consequences of an unhealthy diet and obesity. While electroencephalography (EEG) was recorded, 63 participants completed a computer-based task in which they were first randomly allocated to view either SBB-specific, general, or non-warning control HWLs. They then viewed images of a range of SSB products, varying on perceived healthiness and tastiness, and rated their willingness to consume (WTC) each one. Linear mixed-effect model analyses revealed that general and specific HWLs both decreased WTC SSBs perceived as tasty, compared to the control condition. For general HWLs, this effect was reduced for SSBs perceived to be healthy, suggesting that specific HWLs may be more effective at reducing SSB consumption. The EEG data showed that SSBs considered unhealthy elicited greater N1 amplitudes, and tasty SSBs elicited greater late positive potential (LPP) amplitudes, possibly reflecting attentional allocation and craving responses, respectively. However, no strong differences between HWL types were found. Taken together, the results suggest that graphic HWLs, both general and specific, have the potential to reduce SSB consumption, but they do not strongly modulate craving-related neural responses to SSBs.

Drinking and responses to antidrinking messages among young adults: An fMRI study

Young adults consume most of their alcohol by binge drinking, and more than one-third report binge drinking in the past month. Some will transition out of excessive drinking, while others will maintain or increase alcohol use into adulthood. Public health campaigns depicting negative consequences of drinking have shown some efficacy at reducing this behavior. However, substance use in dependent individuals is governed in part by automatic or habitual responses to drug cues rather than the consequences. This study used functional magnetic resonance imaging to measure neural responses to drinking cues and drinking cues paired with antidrinking messages among young adults who binge drink (N = 30). This study also explored responses to smoking cues and antismoking messages. Neural responses were also compared between drinking/smoking and neutral cues. Self-reported drinking and smoking were collected at baseline, postscan, and 1 month. Results indicate that activity in the ventral striatum-implicated in reward processing-was lower for drinking cues paired with antidrinking messages than drinking cues. This difference was less pronounced in young adults who reported greater baseline past month drinking quantity. Past month drinking quantity decreased from baseline to 1 month. Further, young adults who showed higher activity during antidrinking messages in the medial prefrontal cortex-implicated in processing message self-relevance- reported a greater decrease in past month drinking frequency from baseline to 1 month. Findings may help to identify young adults who are at risk for continued heavy drinking in adulthood and inform interventions aimed to reduce drinking and reward in young adults.

Signs of Warning: Do Health Warning Messages on Sweets Affect the Neural Prefrontal Cortex Activity?

In the global attempt to combat rising obesity rates, the introduction of health warning messages on food products is discussed as one possible approach. However, the perception of graphical health warning messages in the food context and the possible impact that they may have, in particular at the neuronal level, have hardly been studied. Therefore, the aim of this explorative study was to examine consumers’ reactions (measured as neuronal activity and subjective reporting) of two different types of graphical health warning messages on sweets compared to sweets without warning messages. One type used the red road traffic stop sign as graphical information (“Stop”), while the other one used shocking pictures (“Shock”), an approach similar to the images on cigarette packages. The neural response of 78 participants was examined with the neuroimaging technique functional near-infrared spectroscopy (fNIRS). Different hemodynamic responses in the orbitofrontal cortex (OFC), the frontopolar cortex (FOC), and the dorsolateral prefrontal cortex (dlPFC) were observed, regions which are associated with reward evaluation, social behavior consequences, and self-control. Further, the health warning messages were actively and emotionally remembered by the participants. These findings point to an interesting health information strategy, which should be explored and discussed further.

Impact of health warning labels on snack selection: An online experimental study

Excessive consumption of energy-dense food increases the risk of obesity, which in turn increases the risk of non-communicable diseases, including heart disease, type 2 diabetes and most non-smoking-related cancers. Health warning labels (HWLs) that communicate the adverse health consequences of excess energy consumption could reduce intake of energy-dense foods. The aim of the current study was to estimate the impact on selection of energy-dense snacks of (a) image-and-text HWLs (b) text-only HWLs and (c) calorie information. In a between-subjects, 3 (HWL: image-and-text, text-only, no label) x 2 (calorie information: present, absent), factorial experimental design, participants (N = 4134) were randomised to view a selection of energy-dense and non-energy-dense snacks with one of five label types or no label. The primary outcome was the proportion of participants selecting an energy-dense snack in a hypothetical vending machine task. The proportion of participants selecting an energy-dense snack was reduced in all label groups, relative to the no label group (no label: 59%; calories only: 54%; text-only HWL: 48%; text-only HWL with calories: 44%; image-and-text HWL: 37%; image-and-text HWL with calories: 38%). Compared to the no label group, participants were least likely to select an energy-dense snack in the image-and-text HWL group (OR = 0.46, 95%CI = 0.40, 0.54, p < 0.001). Health warning labels - particularly those including an image and text - have the potential to reduce selection of energy-dense snacks in an online setting. Their impact on selection and consumption in real-world settings awaits testing.

Image-and-text health warning labels on alcohol and food: potential effectiveness and acceptability

BACKGROUND

Health warning labels (HWLs) using images and text to depict the negative health consequences of tobacco consumption are effective and acceptable for changing smoking-related outcomes. There is currently limited evidence concerning their potential use for reducing consumption of alcoholic drinks and energy-dense foods. The aim of this research was to describe the potential effectiveness and acceptability of image-and-text (also known as pictorial or graphic) HWLs applied to: i. alcoholic drinks and ii. energy-dense snack foods.

METHODS

Two online studies were conducted using between-subjects designs with general population samples. Participants rated one of 21 image-and-text HWLs on alcoholic drinks (n = 5528), or one of 18 image-and-text HWLs on energy-dense snacks (n = 4618). HWLs comprised a graphic image with explanatory text, depicting, respectively, seven diseases linked to excess alcohol consumption, and six diseases linked to excess energy intake. Diseases included heart disease and various cancers. Outcomes were negative emotional arousal, desire to consume the labelled product, and acceptability of the label. Free-text comments relating to HWLs were content analysed.

RESULTS

For both alcoholic drinks and energy-dense snacks, HWLs depicting bowel cancer generated the highest levels of negative emotional arousal and lowest desire to consume the product, but were the least acceptable. Acceptability was generally low for HWLs applied to alcohol, with 3 of 21 rated as acceptable, and was generally high for snacks, with 13 of 18 rated as acceptable. The majority of free-text comments expressed negative reactions to HWLs on alcohol or energy-dense snacks.

CONCLUSIONS

Image-and-text health warning labels depicting bowel cancer showed greatest potential for reducing selection and consumption of alcoholic drinks and energy-dense snacks, although they were the least acceptable. Laboratory and field studies are needed to assess their impact on selection and consumption.

How Can We Motivate People to Use Nutritional Warnings in Decision Making? Citizen Co-Created Insights for the Development of Communication Campaigns

Nutritional warnings are intended to enable citizens to make informed choice by clearly identifying food products with excessive content of nutrients associated with noncommunicable diseases. The efficacy of this public policy is expected to improve if accompanied by communication campaigns that raise awareness of the existence of nutritional warnings, as well as encourage citizens to take them into account in decision making. Because ordinary citizens have been shown to generate significantly more creative and valuable ideas than advanced users and professional developers, the aim of the present work was to obtain qualitative, citizen co-created insights for the design of a communication campaign. An online study was conducted with 518 Uruguayan citizens, recruited using a Facebook advertisement. Participants were asked to answer a series of open-ended questions about how they would encourage other people to use the warnings for making their food choices, as well as the key contents of a communication campaign. Responses were analyzed using content analysis. Results showed that, according to the participants’ accounts, an effective public awareness campaign aimed at promoting the use of nutritional warnings in decision making should include three main concepts: (a) position warnings as a cue to action for improving eating habits by enabling informed choices; (b) emphasize the benefits of using the warnings for avoiding consumption of unhealthy food and, consequently, achieving a healthier diet and an improvement in health status and quality of life; and (c) increase the perceived susceptibility and severity of the negative consequences of consumption of foods with excessive content of sugar, fat, and sodium. A communication campaign based on these key concepts could contribute to increasing the efficacy of nutritional warnings.

Are Australians ready for warning labels, marketing bans and sugary drink taxes? Two cross-sectional surveys measuring support for policy responses to sugar-sweetened beverages

OBJECTIVE

To assess public support for 10 potential policy initiatives to reduce sugar-sweetened beverage (SSB) consumption.

DESIGN

A 2014 historical data set, which employed a face-to-face survey in one Australian state (study 1), provided the basis for comparison with our 2017 nationally representative, cross-sectional, computer-assisted telephone interviewing population survey (study 2).

PARTICIPANTS

Study 1: South Australians, 15+ years (n=2732); study 2: Australians, 18+ years (n=3430).

PRIMARY OUTCOME MEASURES

levels of support for SSB-specific policy initiatives. For the 2017 national study (study 2), demographic characteristics, body mass index, knowledge of potential harms caused by consuming SSBs and SSB consumption were included in multivariable regression analyses.

RESULTS

In 2017, all 10 potential policy initiatives received majority support (60%-88% either 'somewhat' or 'strongly' in favour). Initiatives with educative elements or focused on children received high support (>70%), with highest support observed for text warning labels on drink containers (88%) and government campaigns warning of adverse health effects (87%). Higher support was observed for SSB tax paired with using funds for obesity prevention (77%) than a stand-alone tax (60%). Support for policy initiatives was generally greater among those who believed SSB daily consumption could cause health problems in adults (4%-18% absolute difference) and/or in children (8%-26% absolute difference) and lower among SSB high consumers (7+ drinks per week; 9%-29% absolute difference). State-specific data comparison indicated increased support from 2014 to 2017 for taxation (42%vs55%; χ²=15.7, p<0.001) and graphic health warnings (52%vs68%; χ²=23.4. p<0.001).

CONCLUSIONS

There is strong public support for government action, particularly regulatory and educational interventions, to reduce SSB consumption, which appears to have increased since 2014. The findings suggest that framing policies as protecting children, presenting taxation of SSBs in conjunction with other obesity prevention initiatives and education focused on the harms associated with SSB consumption will increase support.

Dorsolateral and medial prefrontal cortex mediate the influence of incidental priming on economic decision making in obesity

Obese individuals discount future rewards to a higher degree than lean individuals, which is generally considered disadvantageous. Moreover, their decisions are altered more easily by decision-irrelevant cues. Here, we investigated neural correlates of this phenomenon using functional MRI. We tested 30 lean and 26 obese human subjects on a primed delay discounting paradigm using gustatory and visual cues of positive, neutral and negative valence to bias their intertemporal preferences. We hypothesised that activation differences in reward-related and behavioural control areas, and changes in connectivity between these areas, would reflect the effect of these cues. Here, obese subjects were more susceptible to priming with negative gustatory cues towards delayed choices as opposed to lean subjects. This was related to lower activity in the left dorsolateral prefrontal cortex during priming. Modulation of functional connectivity between the dlPFC and the ventromedial PFC by the behavioural priming effect correlated negatively with BMI. This might indicate that default goals of obese individuals were different from those of lean participants, as the dlPFC has been suggested to be involved in internal goal pursuit. The present results further our understanding of the role of the PFC in decision-making and might inform future weight-management approaches based on non-invasive brain stimulation.

Impact of warning labels on sugar-sweetened beverages on parental selection: An online experimental study

Sugar-sweetened beverages (SSBs) are one of the largest added sugar sources to diets in the UK and USA, particularly among young people. Warning labels, including calorie information labels, could reduce SSB consumption but uncertainty surrounds the labels that are most effective. This study assessed the impact of labels containing (a) each of two image-based warnings and (b) calorie information, singly and together, on SSB selection by parents of 11-16-year-olds living in the UK. Using a 3 (disease image, sugar content image, no image) × 2 (calorie information, no calorie information) between-subjects experimental design, 2002 participants were randomised to see beverages with one of six labels and selected one for their child to consume. The primary outcome was the proportion of participants selecting an SSB. Data were collected in December 2017. Logistic regressions showed SSB selection was lower when labels contained an image-based warning (35%), compared to not having any label (49%) or just calorie information (43.5%). The disease image lowered selection more than the sugar image (32% vs 40.5%). Providing calorie information with the disease image had no additional impact on selection (33%) but enhanced the impact of the sugar image (36%). Image-based warning labels discourage SSB selection by parents for their children. Images depicting health consequences of excess sugar consumption have larger effects than those depicting sugar content. Calorie information does not add to the effect of the former but does to that of the latter. Field studies are needed to assess the impact of SSB warning labels in real-life settings.