Impact of health warning labels on selection and consumption of food and alcohol products: systematic review with meta-analysis

How does habit strength affect reactions to warning labels? evidence from Chinese consumers' choices of carbonated beverages

Effectively regulating the excessive consumption of sugar-sweetened beverages (SSBs) has been an important task for public health authorities around the world. The rapid increase in SSB consumption in China necessitates robust regulations. This study employed a choice experiment to simulate the market scenario in which a text warning label was presented on SSBs. We draw a sample of 1200 participants from five major cities across China to analyze the warning label's effectiveness in reducing urban consumers' purchases of SSBs, with a particular emphasis on how an individual's habit strength affects their reaction to the warning label. Our analysis unveiled varying levels of habit strength among respondents: 35.33% showed weak habits, 56.25% displayed moderate habits, and 8.42% demonstrated strong habits. The random parameters logit model results showed a significant overall decrease in SSB purchases when a warning label was present, indicated by a significant negative coefficient associated with the label. However, when examining the impact of warning labels across different habit strengths, a significant effect was observed only in the moderate habit group. Furthermore, within this group, the warning label was more effective for those with correct health knowledge and who were not overweight or obese.

Health harms that discourage alcohol consumption: A randomized experiment of warning messages

BACKGROUND

Health warnings about alcohol consumption could inform consumers and discourage alcohol consumption, but little is known about what topics these warnings should address. We sought to identify promising topics for alcohol warnings.

METHODS

In January 2024, we recruited a convenience sample of 2,522 US adults ages ≥ 21 years. In an online within-subjects experiment, participants viewed messages about 6 topics (5 warning topics selected from a pool of 16 topics [e.g., liver disease, liver cancer] and 1 control topic [i.e., recycling or reselling products]) shown in random order. For each topic, participants viewed and rated 2 statements about that topic on perceived message effectiveness (primary outcome) and reactance (secondary outcome).

RESULTS

The 16 warning topics elicited higher perceived message effectiveness than the control topic (ps < 0.001). Among the warning topics, liver disease, most cancer types, dementia or mental decline, and hypertension elicited the highest perceived message effectiveness, while breast cancer, sleep, and drinking guidelines elicited the lowest. Fourteen of the 16 warning topics (all except for fetal harms and impaired driving) elicited more reactance than the control topic (ps < 0.001). Warning topics that elicited high perceived message effectiveness generally elicited high reactance, except for messages about liver disease and liver cancer, which elicited high perceived message effectiveness but only moderate reactance.

DISCUSSION

Warning messages about a variety of topics hold promise for discouraging alcohol consumption. Messages about liver disease, most cancer types, dementia or mental decline, and hypertension are perceived as especially effective; however, none of these topics are included in the current US alcohol warning.

Global Trends and Research Collaborations on Food and Beverages Warning Labels: A Bibliometric Analysis

BACKGROUND

Non-communicable diseases (NCDs) represent a global health challenge, accounting for 74% of deaths worldwide. One of the recommended interventions to reduce the risk of NCDs is the implementation of warning labels (WLs) on food products to alert consumers about high levels of undesirable nutrients, such as sugar or saturated fats. We aimed to conduct a bibliometric analysis of scientific literature related to WL policies in food and beverages to evaluate global trends and collaborations.

METHODS

A bibliometric analysis was performed using the Web of Science Core Collection (WoSCC). Articles published between 1998 and 2023 were retrieved using the search terms "warning labels" AND "food" OR "beverage". Bibliometric indicators, including publication counts, citations, collaborations, and thematic trends, were analyzed using the Bibliometrix package in R and VOSviewer.

RESULTS

We included 255 articles on WLs. Scientific production increased markedly from 2018 onwards, with over 30 articles published annually from 2018 to 2023. The most cited article, by Taillie et al., focused on the impact of Chile's WL policies. The United States had the largest scientific production, followed by Brazil and Chile. Nutrients was the journal with the most publications on this topic.

CONCLUSIONS

The growth in WL-related research, particularly in Latin America, reflects the increasing implementation of these policies. These results underscore key collaborations and evolving research themes, from food labeling to broader public health impacts, emphasizing the need for continued evaluation of WL effectiveness.

Effectiveness of alcohol warning labels for at-risk groups and the general public: A policy-informing randomized experiment in Chile

OBJECTIVE

The World Health Organization recommends using health-risk warnings on alcoholic beverages. This study examines the impact of separate or combined warning labels for at-risk groups and the general population on alcohol purchase decisions.

METHODS

In 2022, 7758 adults who consumed alcohol or were pregnant/lactating women (54.0 % female, mean age = 40.6 years) were presented with an online store's beverage section and randomly assigned to one of six warning labels in a between-subjects experimental design: no-warning, pregnant/lactating, drinking-driving, general cancer risk, combined warnings, and assorted warnings across bottles. The main outcome, the intention to purchase an alcoholic vs. non-alcoholic beverage, was examined with adjusted risk differences using logistic regressions.

RESULTS

Participants exposed to the general cancer risk warning decreased their alcoholic choices by 10.4 percentage points (pp.) (95 % CI [-0.139, -0.069], p < 0.001, OR = 0.561), while those in the pregnancy/lactation warning condition did it by 3.8 pp. (95 % CI [-0.071, -0.005], p = 0.025, OR = 0.806). The driving-drinking warning had no significant effect. Participants exposed to the combined warnings label, or the assorted warnings reduced alcohol purchase decisions by 6.1 pp. (95 % CI [-0.095, -0.028], p < 0.001, OR = 0.708) and 4.3 pp. (95 % CI [-0.076, -0.010], p = 0.011, OR = 0.782), respectively. Cancer warning outperformed other labels and was effective for subgroups such as pregnant/lactating women, young adults, and low-income individuals.

CONCLUSIONS

General cancer risk warnings are more effective at reducing alcohol purchase decisions compared to warning labels for specific groups or labels using multiple warnings. In addition to warning labels, other policies should be considered for addressing well-known alcohol-related risks (e.g., drinking and driving).

Can environmental traffic light warning labels reduce meat meal selection? A randomised experimental study with UK meat consumers

An important area for tackling climate change and health improvement is reducing population meat consumption. Traffic light labelling has successfully been implemented to reduce the consumption of unhealthy foods and sugary drinks. The present research extends this work to meat selection. We tested 1,300 adult UK meat consumers (with quotas for age and gender to approximate a nationally representative sample). Participants were randomised into one of four experimental groups: (1) a red traffic light label with the text 'High Climate Impact' displayed on meat meal options only; (2) a green traffic light label with the text 'Low Climate Impact' displayed on vegetarian and vegan meal options only; (3) red/orange/green (ROG) traffic light labels displayed on relevant meals; and (4) control (no label present). Participants made meal selections within their randomised group across 20 meal trials. A beta-regression was performed to ascertain the change in primary outcome (proportion of meat meals selected across the 20 trials) across the different groups. The red-only label and ROG labels significantly reduced the proportion of meat meals selected compared to the unlabelled control group, by 9.2% and 9.8% respectively. The green-only label did not differ from control. Negatively framed traffic light labels seem to be effective at discouraging meat selection. The labels appeared to be moderately acceptable to meat eaters, who did not think the labels impacted the appeal of the products. These encouraging findings require replication in real-life settings.

Impact of text-only versus large text-and-picture alcohol warning formats: A functional magnetic resonance imaging study in French young male drinkers

BACKGROUND

Although the World Health Organization recommends visible and clear warning labels about the risks of alcohol consumption on containers and advertising, many of the currently used labels are too small to be visible. This study investigated the brain activity (using fMRI) and alcohol consumption intentions of French young men exposed to two warning formats displayed on alcoholic beverage advertisements: a small Text-only Alcohol Warning (TAW) currently used in many countries, and a larger text-and-picture alcohol warning (PAW).

METHODS

Seventy-four eligible 18-25-year-old male drinkers completed a face-to-face individual visit with a physician expert in addiction medicine. This was followed by the fMRI session during which they viewed 288 stimuli [96 alcohol advertisements with TAWs, the same 96 advertisements with PAWs, and 96 water advertisements (controls)] for 3 s each. If the advertisement made participants want ("yes")/do not want ("no") to consume the product, they pressed the corresponding button (self-report responses). The number of "yes" responses was compared between advertisement types with a paired sample t-test. Whole-brain and region-of-interest (ROI) analyses of the fMRI data were performed.

RESULTS

Whole-brain BOLD fMRI highlighted contrasting effects of PAWs and TAWs. Compared with TAWs, PAWs elicited more activation in the precuneus, angular gyrus, occipital, frontal and temporal areas, and less activation in the nucleus accumbens, ventral tegmental areas, and putamen areas (regions of the reward circuit). The ROI analysis confirmed less activation in the reward circuit (left and right ventral tegmental areas, left and right nucleus accumbens) when viewing PAWs than TAWs. Analysis of the self-report responses indicated that the desire to consume the advertised alcohol product was lower when PAWs were viewed (compared with TAWs) (T = 8.18, p < 10-11).

CONCLUSIONS

This is the first fMRI study to assess the effect of different alcohol warning formats. Our findings show that compared with TAWs, stronger PAWs in advertisements elicited less activity in key regions of the reward system. This suggests that the effects may influence the desire to consume alcohol products (self-report response analysis). These results could help policymakers who are interested in developing more effective labeling measures that target young people.

Am I a responsible drinker? The impact of message frame and drinker prototypes on perceptions of alcohol product information labels

BACKGROUND

Current alcohol product labelling tends to include ambiguous messages such as 'drink responsibly'. Consumers who identify as responsible drinkers may not pay heed to health warning messages, believing that they are not the intended target.

AIMS

We aimed to determine how responses to responsible drinking labels would differ from responses to positively and negatively framed health messages. We also explored if prototype perceptions would moderate the message impact.

METHODS

A between groups, three arm (ambiguous, positive or negative messages) experiment recruited 465 participants. Outcomes were drinking intentions and label acceptability (novelty, believability, personal relevance, and potential to change behaviour). Measures of heavy and responsible drinker prototype perceptions were included for exploratory moderation analyses.

RESULTS

Positive and negative messages were rated significantly more likely to change behaviour than ambiguous messages. There was also a moderation effect: participants with stronger favourability and similarity to the responsible drinker prototype intended to drink more alcohol in the future after exposure to negatively framed labels, but not after exposure to ambiguous or positively framed labels.

DISCUSSION

Drink responsibly' messages are unlikely to lead to behaviour change. Incorporating theoretical moderators may have value in developing our understanding of the impact of alcohol product labelling.

The effect of information about hazardous chemicals in consumer products on behaviour - A systematic review

Exposure to hazardous chemicals in consumer products poses significant risks to personal health and the environment, and the combined effects may be negative even if each individual exposure is low. This necessitates informed and effective policies for risk reduction. This systematic review aims to identify and analyse existing evidence on how consumer preferences, product use, and product disposal are affected by information on harmful chemicals in consumer products and by price interventions. The review is conducted according to the PRISMA 2020 guidelines, synthesises forty-eight scientific articles on the relationship between information and consumer responses. No corresponding studies on the effects of price interventions were found. A large share of the identified articles focused on household chemicals, where warning labels are common, while less has been published on "everyday products" where the presence of hazardous chemicals is less clear to consumers. Effects of information on hazardous chemicals on consumer behaviour are highly contextual and dependent on the type of product, consumer behaviour and what kind of label is used. Warning symbols are effective in communicating a general warning of a potential danger, although consumers often misinterpret specifics regarding the exact nature of that danger or what means should be taken to minimise it. Informational texts are more informative but are also often missed or quickly forgotten. Consumer willingness to pay for safer products is generally positive but low. Additional research on how consumers react to information and price signals on chemical hazards is needed to improve policy design.

Redesigning Pharmacy to Improve Public Health Outcomes: Expanding Retail Spaces for Digital Therapeutics to Replace Consumer Products That Increase Mortality and Morbidity Risks

United States healthcare outcomes, including avoidable mortality rates, are among the worst of high-income countries despite the highest healthcare spending per capita. While community pharmacies contribute to chronic disease management and preventive medicine, they also offer consumer products that increase mortality risks and the prevalence of cardiovascular diseases, diabetes, cancer, and depression. To resolve these contradictions, our perspective article describes opportunities for major pharmacy chains (e.g., CVS Pharmacy and Walgreens) to introduce digital health aisles dedicated to prescription and over-the-counter digital therapeutics (DTx), together with mobile apps and wearables that support disease self-management, wellness, and well-being. We provide an evidence-based rationale for digital health aisles to replace spaces devoted to sugar-sweetened beverages and other unhealthy commodities (alcohol, tobacco) that may increase risks for premature death. We discuss how digital health aisles can serve as marketing and patient education resources, informing customers about commercially available DTx and other technologies that support healthy lifestyles. Since pharmacy practice requires symbiotic balancing between profit margins and patient-centered, value-based care, replacing health-harming products with health-promoting technologies could positively impact prevention of chronic diseases, as well as the physical and mental health of patients and caregivers who visit neighborhood pharmacies in order to pick up medicines.

A systematic review on the impact of alcohol warning labels

Findings on the effects of alcohol warning labels (AWLs) as a harm reduction tool have been mixed. This systematic review synthesized extant literature on the impact of AWLs on proxies of alcohol use. PsycINFO, Web of Science, PubMED, and MEDLINE databases and reference lists of eligible articles. Following PRISMA guidelines, 1,589 articles published prior to July 2020 were retrieved via database and 45 were via reference lists (961 following duplicate removal). Article titles and abstracts were screened, leaving the full text of 96 for review. The full-text review identified 77 articles meeting inclusion/exclusion criteria which are included here. Risk of bias among included studies was examined using the Evidence Project risk of bias tool. Findings fell into five categories of alcohol use proxies including knowledge/awareness, perceptions, attention, recall/recognition, attitudes/beliefs, and intentions/behavior. Real-world studies highlighted an increase in AWL awareness, alcohol-related risk perceptions (limited findings), and AWL recall/recognition post-AWL implementation; these findings have decreased over time. Conversely, findings from experimental studies were mixed. AWL content/formatting and participant sociodemographic factors also appear to influence the effectiveness of AWLs. Findings suggest conclusions differ based on the study methodology used, favoring real-world versus experimental studies. Future research should consider AWL content/formatting and participant sociodemographic factors as moderators. AWLs appear to be a promising approach for supporting more informed alcohol consumption and should be considered as one component in a comprehensive alcohol control strategy.

Can a health warning label diminish the persuasive effects of health-oriented nutrition advertising on ready-to-drink alcohol product packaging? A randomized experiment

BACKGROUND AND AIMS

A health warning label (HWL) cautioning about the link between alcohol and cancer may be able to communicate alcohol risks to consumers and potentially counter health-oriented nutrition advertising on ready-to-drink alcoholic beverages. This study aimed to examine the independent and combined effects of nutrient content claims (e.g. 0 g sugar) and a HWL on perceived product characteristics and intentions to consume, and whether these effects differed by gender and age.

DESIGN

A between-subjects randomized experiment. Participants were randomized to view one of six experimental label conditions: nutrient content claims plus nutrition declaration (NCC + ND), ND only, NCC + ND + HWL, ND + HWL, HWL only and no NCC, ND or HWL, all on a ready-to-drink (RTD) vodka-based soda container.

SETTING AND PARTICIPANTS

Alcohol consumers (n = 5063; 52% women) in Canada aged 18-64 recruited through a national online panel.

MEASUREMENTS

Participants completed ratings of perceived product characteristics, perceived product health risks, and intentions to try, buy, binge and drink the product.

FINDINGS

Compared with the reference condition NCC + ND (current policy scenario in Canada), the other five experimental label conditions were associated with lower ratings for perceiving the product as healthy. All experimental conditions with a HWL were associated with lower product appeal, higher risk perceptions and reduced intentions to try, buy and binge. The experimental condition with a HWL only was associated with intentions to consume fewer cans in the next 7 days (β = -0.72, 95% confidence interval [CI] = -1.37,-0.08) versus the reference. Few interactions were observed, suggesting that label effects on outcomes were similar by gender and age.

CONCLUSIONS

Health warning labels on alcohol packaging appear to be associated with lower product appeal, higher perceived health risks and reduced consumption intentions, even in the presence of nutrient content claims.

The effects of alcohol container labels on consumption behaviour, knowledge, and support for labelling: a systematic review

Alcohol container labels might reduce population-level alcohol-related harms, but investigations of their effectiveness have varied in approach and quality. A systematic synthesis is needed to adjust for these differences and to yield evidence to inform policy. Our objectives were to establish the effects of alcohol container labels bearing one or more health warnings, standard drink information, or low-risk drinking guidance on alcohol consumption behaviour, knowledge of label message, and support for labels. We completed a systematic review according to Cochrane and synthesis without meta-analysis standards. We included all peer-reviewed studies and grey literature published from Jan 1, 1989, to March 6, 2024, in English, French, German, or Spanish that investigated the effects of alcohol container labels compared with no-label or existing label control groups in any population on alcohol consumption behaviour, knowledge of label message, or support for labels. Data were synthesised narratively as impact statements and assessed for risk of bias and certainty in the evidence. A protocol was preregistered (PROSPERO CRD42020168240). We identified 40 publications that studied 31 labels and generated 17 impact statements. 24 (60%) of 40 publications focused on consumption behaviour and we had low or very low certainty in 13 (59%) of 22 outcomes. Alcohol container labels bearing health warnings might slow the rate of alcohol consumption (low certainty), reduce alcoholic beverage selection (moderate certainty), reduce consumption during pregnancy (low certainty), and reduce consumption before driving (moderate certainty). Interventions with multiple types of rotating alcohol container labels likely substantially decrease alcohol use (moderate certainty) and reduce alcohol sales (high certainty). To the best of our knowledge, this is the first systematic review on multiple types of alcohol container labels assessing their effects for certainty in the evidence. Limitations included heterogeneity in label designs and outcome measurements. Alcohol container labels probably influence some alcohol consumption behaviour, with multiple rotating messages being particularly effective, although effects might vary depending on individual health literacy or drinking behaviour. Alcohol container labels might therefore be effective components of policies designed to address population-level alcohol-related harms.

How Promising Are "Ultraprocessed" Front-of-Package Labels? A Formative Study with US Adults

High levels of food processing can have detrimental health effects independent of nutrient content. Experts and advocates have proposed adding information about food processing status to front-of-package labeling schemes, which currently exclusively focus on nutrient content. How consumers would perceive "ultraprocessed" labels has not yet been examined. To address this gap, we conducted a within-subjects online experiment with a convenience sample of 600 US adults. Participants viewed a product under three labeling conditions (control, "ultraprocessed" label, and "ultraprocessed" plus "high in sugar" label) in random order for a single product. The "ultraprocessed" label led participants to report thinking more about the risks of eating the product and discouraging them from wanting to buy the product more than the control, despite not grabbing more attention than the control. The "ultraprocessed" plus "high in sugar" labels grabbed more attention, led participants to think more about the risks of eating the product, and discouraged them from wanting to buy the product more than the "ultraprocessed" label alone. "Ultraprocessed" labels may constitute promising messages that could work in tandem with nutrient labels, and further research should examine how they would influence consumers' actual intentions and behaviors.

Understanding Whether Price Tag Messaging Can Amplify the Benefits of Taxes: An Online Experiment

INTRODUCTION

Excise taxes on unhealthy products like sugary drinks and tobacco can reduce purchases of these products. However, little research has investigated whether messages at the point of purchase, such as enhanced price tags, can increase the effects of taxes by heightening psychological reactions. This study aimed to examine whether including messages about taxes on price tags could amplify the benefits of excise taxes on unhealthy products.

METHODS

In 2022, an online study recruited 1,013 U.S. parents to view seven price tag messages (e.g., "includes a 19% sugary drink tax") and a control (i.e., standard price tag with the tax included in the price) displayed in random order alongside sugary drinks. Participants were randomly assigned to view a caution-symbol icon or no icon on price tags. Analyses were conducted in 2023.

RESULTS

All seven messages discouraged parents from buying sugary drinks for their children compared to control (average differential effects [ADEs] ranged from 0.28 to 0.48, all p<0.001). All messages led to greater attention to the price tag (ADEs ranged from 0.24 to 0.41, all p<0.001) and greater consideration of the cost of sugary drinks (ADEs ranged from 0.31 to 0.50, all p<0.001). Icons elicited higher cost consideration than text-only price tags (ADE=0.15, p<0.010), but not discouragement (p=0.061) or attention (p=0.079).

CONCLUSIONS

Messaging on price tags could make excise taxes more effective. Policymakers should consider requiring messaging on price tags when implementing taxes.

Qualitative analysis of UK women's attitudes to calorie-based alcohol marketing and alcohol calorie labelling

Mandatory standardized nutritional information on alcoholic drinks such as energy, or calorie labelling, is a population-level public health measure aimed at addressing obesity and alcohol consumption. In the UK, such measures are not a statutory requirement, but some alcohol brands do include references to calories on their products and in their marketing materials, as a marketing strategy to encourage sales and consumption. This article presents findings of semi-structured individual (N = 43) and group (N = 9) interviews with 78 women living in the UK that aimed to gain insight into their attitudes towards calorie-based alcohol brand marketing, and alcohol calorie labelling (ACL) as a health policy. Three themes are presented that outline how women rejected calorie marketing and labelling; the potential positive and unintended impact on alcohol consumption and dietary/eating practices; and how views on calorie labelling were intertwined with women's attitudes towards marketing that draws on calorie messaging. A feminist anti-diet discourse, as well as a discourse of pleasure through alcohol consumption, was at play in women's accounts, which may limit the intended aims of ACLs. It is concluded that ACLs should be considered within the wider commercial context of alcohol marketing that draws on calories to promote sales and consumption, consideration of the gendered factors that may lead some to reject ACLs as a health policy, and the potential for unintended consequences.

Impact of health warning labels and calorie labels on selection and purchasing of alcoholic and non-alcoholic drinks: A randomized controlled trial

AIMS

To estimate the impact on selection and actual purchasing of (a) health warning labels (text-only and image-and-text) on alcoholic drinks and (b) calorie labels on alcoholic and non-alcoholic drinks.

DESIGN

Parallel-groups randomised controlled trial.

SETTING

Drinks were selected in a simulated online supermarket, before being purchased in an actual online supermarket.

PARTICIPANTS

Adults in England and Wales who regularly consumed and purchased beer or wine online (n = 651). Six hundred and eight participants completed the study and were included in the primary analysis.

INTERVENTIONS

Participants were randomized to one of six groups in a between-subjects three [health warning labels (HWLs) (i): image-and-text HWL; (ii) text-only HWL; (iii) no HWL] × 2 (calorie labels: present versus absent) factorial design (n per group 103-113).

MEASUREMENTS

The primary outcome measure was the number of alcohol units selected (with intention to purchase); secondary outcomes included alcohol units purchased and calories selected and purchased. There was no time limit for selection. For purchasing, participants were directed to purchase their drinks immediately (although they were allowed up to 2 weeks to do so).

FINDINGS

There was no evidence of main effects for either (a) HWLs or (b) calorie labels on the number of alcohol units selected (HWLs: F(2,599)  = 0.406, P = 0.666; calorie labels: F(1,599)  = 0.002, P = 0.961). There was also no evidence of an interaction between HWLs and calorie labels, and no evidence of an overall difference on any secondary outcomes. In pre-specified subgroup analyses comparing the 'calorie label only' group (n = 101) with the 'no label' group (n = 104) there was no evidence that calorie labels reduced the number of calories selected (unadjusted means: 1913 calories versus 2203, P = 0.643). Among the 75% of participants who went on to purchase drinks, those in the 'calorie label only' group (n = 74) purchased fewer calories than those in the 'no label' group (n = 79) (unadjusted means: 1532 versus 2090, P = 0.028).

CONCLUSIONS

There was no evidence that health warning labels reduced the number of alcohol units selected or purchased in an online retail context. There was some evidence suggesting that calorie labels on alcoholic and non-alcoholic drinks may reduce calories purchased from both types of drinks.

Impact of pictorial warning labels on meat meal selection: A randomised experimental study with UK meat consumers

Meat consumption has been linked to adverse health consequences, worsening climate change, and the risk of pandemics. Meat is however a popular food product and dissuading people from consuming meat has proven difficult. Outside the realm of meat consumption, previous research has shown that pictorial warning labels are effective at curbing tobacco smoking and reducing the consumption of sugary drinks and alcohol. The present research extends this work to hypothetical meat meal selection, using an online decision-making task to test whether people's meal choices can be influenced by pictorial warning labels focused on the health, climate, or pandemic risks associated with consuming meat. Setting quotas for age and gender to approximate a UK nationally representative sample, a total of n = 1001 adult meat consumers (aged 18+) were randomised into one of four experimental groups: health pictorial warning label, climate pictorial warning label, pandemic pictorial warning label, or control (no warning label present). All warning labels reduced the proportion of meat meals selected significantly compared to the control group, with reductions ranging from -7.4% to -10%. There were no statistically significant differences in meat meal selection between the different types of warning labels. We discuss implications for future research, policy, and practice.

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.

Effects of 4 Interpretive Front-of-Package Labeling Systems on Hypothetical Beverage and Snack Selections: A Randomized Clinical Trial

Importance

Policymakers and researchers have proposed a variety of interpretative front-of-package food labeling systems, but it remains unclear which is most effective at encouraging people to choose healthier foods and beverages, including among people with less education.

Objective

To test the effects of 4 interpretative front-of-package food labeling systems on the healthfulness of beverage and snack selections, overall and by education level.

Design, Setting, and Participants

This randomized clinical trial of a national sample of US adults 18 years and older was conducted online from November 16 to December 3, 2022.

Intervention

Participants were randomized to view products with 1 of 5 food labeling systems, including control (calorie labels only) or 1 of 4 interpretative labeling systems: green ("choose often") labels added to healthy foods; single traffic light labels added to healthy, moderately healthy, and unhealthy foods; physical activity calorie equivalent labels added to all products; and nutrient warning labels added to products high in calories, sugar, saturated fat, or sodium. All conditions had calorie labels on all products.

Main Outcomes and Measures

Participants selected 1 of 16 beverages and 1 of 16 snacks that they wanted to hypothetically purchase. The primary outcomes were calories selected from beverages and from snacks. Secondary outcomes included label reactions and perceptions.

Results

A total of 7945 participants completed the experiment and were included in analyses (4078 [51%] female, 3779 [48%] male, and 88 [1%] nonbinary or another gender; mean [SD] age, 47.5 [17.9 years]). Compared with the control arm, exposure to the green (average differential effect [ADE], -34.2; 95% CI, -42.2 to -26.1), traffic light (ADE, -31.5; 95% CI, -39.5 to -23.4), physical activity (ADE, -39.0; 95% CI, -47.0 to -31.1), or nutrient warning labels (ADE, -28.2; 95% CI, -36.2 to -20.2) led participants to select fewer calories from beverages (all P < .001). Similarly, compared with the control label, exposure to the green (ADE, -12.7; 95% CI, -17.3 to -8.2), traffic light (ADE, -13.7; 95% CI, -18.2 to -9.1), physical activity (ADE, -18.5; 95% CI, -23.1 to -13.9), or nutrient warning labels (ADE, -14.2; 95% CI, -18.8 to -9.6) led participants to select fewer calories from snacks (all P < .001). These effects did not differ by education level. The green labels were rated as less stigmatizing than the other interpretative systems but otherwise generally received the least favorable label reactions and perceptions (eg, elicited less attention, were perceived as less trustworthy), while the nutrient warnings and physical activity labels received the most favorable ratings.

Conclusions and Relevance

In this randomized clinical trial of front-of-package food labeling systems, all 4 interpretative labeling systems reduced calories selected from beverages and from snacks compared with calorie labels, with no differences by education level.

Trial Registration

ClinicalTrials.gov Identifier: NCT05432271.

Effects of pictorial warnings on parents' purchases and perceptions of sugar-sweetened beverage categories

BACKGROUND

Sugar-sweetened beverage (SSB) consumption remains high among US children. Warning labels on SSBs hold promise for reducing consumption, but their impact may differ by SSB category.

OBJECTIVES

This study examined the effects of pictorial warnings on parents' beverage purchases and perceptions across SSB categories.

METHODS

Parents of children ages 2-12 (n = 326) visited a convenience store laboratory in North Carolina. Participants were randomly assigned to see SSBs carrying either pictorial warning labels or control labels. Parents purchased a beverage for their child and completed a survey.

RESULTS

Responses from parents in the control arm suggest underlying perceptions of flavoured milk (2.8 on scale ranging from 1 to 5), flavoured water (2.6), and fruit-flavoured drinks (2.5) as the most healthful SSB categories. Compared to the control, pictorial warnings led to the largest reductions in purchases of fruit drinks (-61%), soda (-36%) and flavoured milk (-32%). Warnings also lowered the perceived healthfulness of flavoured water (d = -0.34), flavoured milk (d = -0.28), sports drinks (d = -0.25), and a reduction in intentions to give one's child sports drinks (d = -0.30), flavoured water (d = -0.24) and sweet tea (d = -0.22, all p < 0.05).

CONCLUSIONS

Warning labels may have heterogeneous effects across SSB categories. Future research should assess the psychological mechanisms underlying these heterogeneous effects.

Impact of Health, Environmental, and Animal Welfare Messages Discouraging Red Meat Consumption: An Online Randomized Experiment

BACKGROUND

Reducing red meat consumption is a key strategy for curbing diet-related chronic diseases and mitigating environmental harms from livestock farming. Messaging interventions aiming to reduce red meat consumption have focused on communicating the animal welfare, health, or environmental harms of red meat. Despite the popularity of these 3 approaches, it remains unknown which is most effective, as limited studies have compared them side by side.

OBJECTIVE

Our aim was to evaluate responses to red-meat-reduction messages describing animal welfare, health, or environmental harms.

DESIGN

This was an online randomized experiment.

PARTICIPANTS

In August 2021, a convenience sample of US adults was recruited via an online panel to complete a survey (n = 2,773 nonvegetarians and vegans were included in primary analyses).

INTERVENTION

Participants were randomly assigned to view 1 of the 4 following messages: control (neutral, non-red meat message), animal welfare, health, or environmental red-meat-reduction messages.

MAIN OUTCOME MEASURES

After viewing their assigned message, participants ordered hypothetical meals from 2 restaurants (1 full service and 1 quick service) and rated message reactions, perceptions, and intentions.

STATISTICAL ANALYSES PERFORMED

Logistic and linear regressions were performed.

RESULTS

Compared with the control message, exposure to the health and environmental red-meat-reduction messages reduced red meat selection from the full-service restaurant by 6.0 and 8.8 percentage points, respectively (P = .02 and P < .001, respectively), while the animal welfare message did not (reduction of 3.3 percentage points, P = .20). None of the red-meat-reduction messages affected red meat selection from the quick-service restaurant. All 3 red-meat-reduction messages elicited beneficial effects on key predictors of behavior change, including emotions and thinking about harms.

CONCLUSIONS

Red-meat-reduction messages, especially those describing health or environmental harms, hold promise for reducing red meat selection in some types of restaurants. Additional interventions may be needed to discourage red meat selection across a wider variety of restaurants, for example, by making salient which menu items contain red meat.

Designing Effective Alcohol Warnings: Consumer Reactions to Icons and Health Topics

Introduction

New warning labels for alcohol could reduce alcohol-related health harms. This study examined consumer responses to alcohol warnings with different designs.

Methods

A national sample of 3,051 U.S. adults completed an online survey in August 2021. Participants were randomized to 1 of 4 warning topics (addiction, liver damage, early death, or colon cancer). Participants viewed 3 labels, presented in random order: 2 types of warning labels (text-only and icon) showing a newly developed warning message about their assigned topic and a text-only control label showing a neutral message. Participants rated each label on effectiveness at discouraging alcohol consumption (primary outcome) and attention (secondary outcome) using 1 to 5 Likert-type scales. Participants also rated warnings with different causal language variants (e.g., "increases risk of," "contributes to") and marker words (e.g., "WARNING," "SURGEON GENERAL WARNING").

Results

Both the text-only and icon warnings were perceived as more effective (Average Differential Effects [ADEs]=0.79 and 0.86, respectively) and more attention-grabbing (ADEs=0.43 and 0.69, respectively) than control labels (all ps<0.001). The icon warnings were rated as more effective and attention-grabbing than the text-only warnings (ADEs=0.07 and 0.27, respectively, both ps<0.001). Although all warning topics outperformed the control messages, warnings about addiction were rated as less effective and attention-grabbing than the other topics. A majority (60%) of participants selected "increases risk of" as the most discouraging causal variant and a plurality (47%) selected "SURGEON GENERAL WARNING" as the most discouraging marker word.

Conclusions

New alcohol warnings could discourage alcohol consumption, especially if warnings include icons.

Effect of salt reduction interventions in lowering blood pressure: A comprehensive systematic review and meta-analysis of controlled clinical trials

BACKGROUND

Excessive salt intake results in hypertension (HTN), which is a major risk factor for cardiovascular disease (CVD). This review and meta-analysis aimed to evaluate the effect of salt reduction interventions on systolic blood pressure (SBP) and diastolic blood pressure (DBP).

METHODS

Studies were identified via systematic searches of the databases, including PubMed, Embase, Scopus, and Web of Science. All the studies examining the effectiveness of salt reduction interventions on blood pressure (BP), regardless of age, sex, and HTN status, were included in the systematic review, and eligible studies were used in the meta-analysis. A random-effect model was applied for quantitative data synthesis.

RESULTS

A total of 50 trials extracted from 40 articles (21 trials on nutrition education,10 on self-help materials,17 on salt substitutes, and 2 on food reformulation) were included in the systematic review. The pooled results of 44 eligible trials showed that salt substitution and nutrition education interventions had significant effects on both SBP (WMD: -7.44 mmHg, P<0.001 and WMD: -2.75 mmHg, P<0.001, respectively), and DBP (WMD: -3.77 mmHg, P<0.001 and WMD: -2.11 mmHg, P<0.001, respectively). Furthermore, using self-help materials led to a significant reduction in SBP among subjects aged 25-60 years (WMD: -2.60 mmHg, P = 0.008); it also decreased both SBP and DBP among those who were hypertensive (WMD: -3.87 mmHg, P = 0.003 and WMD: -2.91 mmHg, P<0.001, respectively).

CONCLUSION

Our results supported that salt substitution and nutrition education are effective nutrition strategies to lower BP. It seems that multi-component approaches could be more effective in improving BP status. However, further trials are required.

The influence of front-of-pack nutritional labels on eating and purchasing behaviors: a narrative review of the literature

BACKGROUND

Front-of-Pack Nutritional Labels are considered a useful tool to help consumers orient themselves in their food choices and direct their behavior toward a healthier diet. FOPNL development and use are part of a framework that includes cognitive, biological, hedonic and cultural aspects, able to affect consumers' eating and purchasing behavior.

AIM

Given the complexity of the matter, the aim of this narrative review is to analyze the combination of different factors that drive food choices and eating behaviors and to highlight some aspects that are not fully studied.

METHODS

The authors conducted the research using a top-down approach at first, followed by a bottom-up approach; starting with general considerations about the purchasing process, gradually narrowing the discussion to a specific sub-population, and finally extending the discussion back to more general reasonings about the direction to adopt in future, or at least to evaluate, for effective communication.

RESULTS

Biases and attitudes toward food products were found to regularly interfere with buying behavior patterns, making it impossible to standardize an average consumer. This reflects in current research, increasing the complexity of the topic. All determinants influencing food choices are often assessed individually rather than in a synergistic and multidimensional context, while the purchasing scenario is characterized by multiple stimuli to which the consumer is subjected. FOPNLs' impact on perceived healthiness has been studied in different conditions, but some population subgroups have not been sufficiently represented. In particular, the effect of FOPNLs on consumers suffering from eating disorders is understudied and needs further attention. Furthermore, some approaches can be compared to "negative nutrition" or "loss-framed communication", putting nutrients out of context, emphasizing losses more than gains and risking promoting negative feelings in consumers.

CONCLUSION

Due to the heterogeneity of studies, evidence on what works best in driving people to adopt lasting lifestyle changes is still mixed. Science communicators and policymakers should consider the possibility that a multi-component approach incorporating nutrition information and education may be a key strategy to promote consumers' self-consciousness and to support them in their cognitive efforts toward a healthy and sustainable diet.

LEVEL OF EVIDENCE

Level V, narrative review.

Obesity in Children

Child obesity is widely prevalent, and general pediatricians play an important role in identifying and caring for patients with obesity. Appropriate evaluation and treatment require an understanding of the complex etiology of child obesity, its intergenerational transmission, and its epidemiologic trends, including racial/ethnic and socioeconomic disparities. The American Academy of Pediatrics has published screening, evaluation, and treatment guidelines based on the best available evidence. However, gaps in evidence remain, and implementation of evidence-based recommendations can be challenging. It is important to review optimal care in both the primary care and multidisciplinary weight management settings. This allows for timely evaluation and appropriate referrals, with the pediatrician playing a key role in advocating for patients at higher risk. There is also a role for larger-scale prevention and policy measures that would not only aid pediatricians in managing obesity but greatly benefit child health on a population scale.

Evaluation of physical activity calorie equivalent (PACE) labels' impact on energy purchased in cafeterias: A stepped-wedge randomised controlled trial

BACKGROUND

A recent meta-analysis suggested that using physical activity calorie equivalent (PACE) labels results in people selecting and consuming less energy. However, the meta-analysis included only 1 study in a naturalistic setting, conducted in 4 convenience stores. We therefore aimed to estimate the effect of PACE labels on energy purchased in worksite cafeterias in the context of a randomised study design.

METHODS AND FINDINGS

A stepped-wedge randomised controlled trial (RCT) was conducted to investigate the effect of PACE labels (which include kcal content and minutes of walking required to expend the energy content of the labelled food) on energy purchased. The setting was 10 worksite cafeterias in England, which were randomised to the order in which they introduced PACE labels on selected food and drinks following a baseline period. There were approximately 19,000 workers employed at the sites, 72% male, with an average age of 40. The study ran for 12 weeks (06 April 2021 to 28 June 2021) with over 250,000 transactions recorded on electronic tills. The primary outcome was total energy (kcal) purchased from intervention items per day. The secondary outcomes were: energy purchased from non-intervention items per day, total energy purchased per day, and revenue. Regression models showed no evidence of an overall effect on energy purchased from intervention items, -1,934 kcals per site per day (95% CI -5,131 to 1,262), p = 0.236, during the intervention relative to baseline, equivalent to -5 kcals per transaction (95% CI -14 to 4). There was also no evidence for an effect on energy purchased from non-intervention items, -5 kcals per site per day (95% CI -513 to 504), p = 0.986, equivalent to 0 kcals per transaction (95% CI -1 to 1), and no clear evidence for total energy purchased -2,899 kcals per site (95% CI -5,810 to 11), p = 0.051, equivalent to -8 kcals per transaction (95% CI -16 to 0). Study limitations include using energy purchased and not energy consumed as the primary outcome and access only to transaction-level sales, rather than individual-level data.

CONCLUSION

Overall, the evidence was consistent with PACE labels not changing energy purchased in worksite cafeterias. There was considerable variation in effects between cafeterias, suggesting important unmeasured moderators.

TRIAL REGISTRATION

The study was prospectively registered on ISRCTN (date: 30.03.21; ISRCTN31315776).

"No Child or Adult Would Ever Probably Choose to Have 16 Teaspoons of Sugar": A Preliminary Study of Parents' Responses to Sugary Drink Warning Label Options

Front-of-pack (FoP) warning labels are a viable policy option with the potential to inform consumer choice and assist in reducing sugar-sweetened beverage (SSB) consumption as part of a multi-faceted approach. This study explored parents' perceptions and understanding of a range of SSB warning labels. Focus groups (n = 12) with 82 parents of school-aged children were conducted, stratified according to education level, sex and location. Health effects, exercise equivalents, sugar content (teaspoons in text and pictograms, "high in") and energy content labels were shown. Through thematic analysis we identified three themes. Theme 1 related to perceptions of effectiveness of labels, underpinned by four subthemes: perceptions of labels as credible, informative and useful, personally relevant and having the potential to change be haviour. Theme 2 related to participants finding opportunities for self-exemption (e.g., physically active) and message rejection (e.g., misinterpretation). Theme 3 encompassed the potential negative consequences of some labels (e.g., body image concerns). The text teaspoons label was perceived most favourably across all themes, with minimal negative issues raised. These results provide in-depth insight into potential responses to labelling as a policy intervention, providing important guidance for the development of labels to ensure optimal message content and framing for future testing and subsequent implementation.

Alcohol Health Warning Labels: A Rapid Review with Action Recommendations

A rapid review of research on health warning labels located on alcohol containers (AWLs) was conducted. Using five search engines (Embase, Medline, Pubmed, Scopus, Psyinfo), 2975 non-duplicate citations were identified between the inception date of the search engine and April 2021. Of those, 382 articles were examined and retrieved. We selected 122 research papers for analysis and narrative information extraction, focusing on population foci, study design, and main outcomes. Research included public opinion studies, surveys of post-AWL implementation, on-line and in-person experiments and real-world quasi-experiments. Many studies focused on the effects of the 1989 United States Alcoholic Beverage Labeling Act on perceptions, intentions and behavior. Others focused on Australia, Canada, the United Kingdom, England or Scotland, Italy and France. There was substantial variation in the design of the studies, ranging from small-scale focus groups to on-line surveys with large samples. Over time, evidence has been emerging on label design components, such as large size, combination of text and image, and specific health messaging, that is likely to have some desired impact on knowledge, awareness of risk and even the drinking behavior of those who see the AWLs. This body of evidence provides guidance to policy-makers, and national and regional authorities, and recommendations are offered for discussion and consideration.

The Role of Narrative Pictorial Warning Labels in Communicating Alcohol-Related Cancer Risks

This study examined the role of pictorial warning labels (PWLs) featuring narrative content in communicating alcohol-related cancer risks. In an online experiment, 169 adult alcohol consumers were randomly assigned to view two narrative PWLs, two non-narrative PWLs, or control. Results showed that exposure to narrative PWLs significantly increased participants' worry about, feelings of risk of, and perceived severity of harm of getting alcohol-related cancer, but did not affect their comparative likelihood of getting alcohol-related cancer or intentions to reduce alcohol use. Exposure to narrative PWLs also indirectly influenced intentions through increased worry. Moreover, participants' risk perceptions and intentions in non-narrative PWLs condition did not differ from those in narrative PWLs and control conditions. Therefore, these findings suggest that narrative PWLs are a promising strategy in informing consumers about the cancer risks of alcohol.

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.

Developing health and environmental warning messages about red meat: An online experiment

INTRODUCTION

The United States has among the highest per capita red meat consumption in the world. Reducing red meat consumption is crucial for minimizing the environmental impact of diets and improving health outcomes. Warning messages are effective for reducing purchases of products like sugary beverages but have not been developed for red meat. This study developed health and environmental warning messages about red meat and explored participants' reactions to these messages.

METHODS

A national convenience sample of US red meat consumers (n = 1,199; mean age 45 years) completed an online survey in 2020 for this exploratory study. Participants were randomized to view a series of either health or environmental warning messages (between-subjects factor) about the risks associated with eating red meat. Messages were presented in random order (within-subjects factor; 8 health messages or 10 environmental messages). Participants rated each warning message on a validated 3-item scale measuring perceived message effectiveness (PME), ranging from 1 (low) to 5 (high). Participants then rated their intentions to reduce their red meat consumption in the next 7 days.

RESULTS

Health warning messages elicited higher PME ratings than environmental messages (mean 2.66 vs. 2.26, p<0.001). Health warning messages also led to stronger intentions to reduce red meat consumption compared to environmental messages (mean 2.45 vs. 2.19, p<0.001). Within category (health and environmental), most pairwise comparisons of harms were not statistically significant.

CONCLUSIONS

Health warning messages were perceived to be more effective than environmental warning messages. Future studies should measure the impact of these messages on behavioral outcomes.

Awareness of and reactions to health and environmental harms of red meat among parents in the United States

OBJECTIVE

Evidence of the health and environmental harms of red meat is growing, yet little is known about which harms may be most impactful to include in meat reduction messages. This study examined which harms consumers are most aware of and which most discourage them from wanting to eat red meat.

DESIGN

Within-subjects randomised experiment. Participants responded to questions about their awareness of, and perceived discouragement in response to, eight health and eight environmental harms of red meat presented in random order. Discouragement was assessed on a 1-to-5 Likert-type scale.

SETTING

Online survey.

PARTICIPANTS

544 US parents.

RESULTS

A minority of participants reported awareness that red meat contributes to health harms (ranging from 8 % awareness for prostate cancer to 28 % for heart disease) or environmental harms (ranging from 13 % for water shortages and deforestation to 22 % for climate change). Among specific harms, heart disease elicited the most discouragement (mean = 2·82 out of 5), followed by early death (mean = 2·79) and plants and animals going extinct (mean = 2·75), though most harms elicited similar discouragement (range of means, 2·60-2·82). In multivariable analyses, participants who were younger, identified as Black, identified as politically liberal, had higher general perceptions that red meat is bad for health and had higher usual red meat consumption reported being more discouraged from wanting to eat red meat in response to health and environmental harms (all P < 0·05).

CONCLUSIONS

Messages about a variety of health and environmental harms of red meat could inform consumers and motivate reductions in red meat consumption.

Designing Environmental Messages to Discourage Red Meat Consumption: An Online Experiment

Reducing red meat consumption in high-consuming countries is critical for mitigating climate change and preventing chronic disease. This study tested the effectiveness of messages conveying the worsening or reduction of environmental harms at discouraging red meat consumption. 1078 U.S. adults viewed seven messages in an online survey highlighting the reduction or worsening of environmental harms associated with eating red meat (between-subjects factor) and rated the messages on how much they discouraged them from wanting to buy beef. Each message highlighted a different environmental harm: deforestation, climate change, water shortages, biodiversity loss, carbon footprint, greenhouse gas emissions, or environment (within-subjects factor). No statistically significant difference was found between the reduction and worsening of environmental harms conditions for most topics, though the worsening of harms frame slightly outperformed the reduction of harms frame for the 'environment' topic. 'Environment' was also the message topic that elicited the strongest response from participants overall. Latino participants, those with more than a high school degree, and those who consume beef once a week or less rated messages as more effective than non-Latino participants, those who completed high school or less, and those who consumed beef more than once a week. Future research should explore the effect of messages on behavioral outcomes.

Visualising health risks with medical imaging for changing recipients' health behaviours and risk factors: Systematic review with meta-analysis

BACKGROUND

There is ongoing clinical and research interest in determining whether providing personalised risk information could motivate risk-reducing health behaviours. We aimed to assess the impact on behaviours and risk factors of feeding back to individuals' images of their bodies generated via medical imaging technologies in assessing their current disease status or risk.

METHODS AND FINDINGS

A systematic review with meta-analysis was conducted using Cochrane methods. MEDLINE, Embase, PsycINFO, CINAHL, and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched up to July 28, 2021, with backward and forward citation searches up to July 29, 2021. Eligible studies were randomised controlled trials including adults who underwent medical imaging procedures assessing current health status or risk of disease, for which personal risk may be reduced by modifying behaviour. Trials included an intervention group that received the imaging procedure plus feedback of visualised results and assessed subsequent risk-reducing health behaviour. We examined 12,620 abstracts and included 21 studies, involving 9,248 randomised participants. Studies reported on 10 risk-reducing behaviours, with most data for smoking (8 studies; n = 4,308), medication use (6 studies; n = 4,539), and physical activity (4 studies; n = 1,877). Meta-analysis revealed beneficial effects of feedback of visualised medical imaging results on reduced smoking (risk ratio 1.11, 95% confidence interval [CI] 1.01 to 1.23, p = 0.04), healthier diet (standardised mean difference [SMD] 0.30, 95% CI 0.11 to 0.50, p = 0.003), increased physical activity (SMD 0.11, 95% CI 0.003 to 0.21, p = 0.04), and increased oral hygiene behaviours (SMD 0.35, 95% CI 0.13 to 0.57, p = 0.002). In addition, single studies reported increased skin self-examination and increased foot care. For other behavioural outcomes (medication use, sun protection, tanning booth use, and blood glucose testing) estimates favoured the intervention but were not statistically significant. Regarding secondary risk factor outcomes, there was clear evidence for reduced systolic blood pressure, waist circumference, and improved oral health, and some indication of reduced Framingham risk score. There was no evidence of any adverse effects, including anxiety, depression, or stress, although these were rarely assessed. A key limitation is that there were some concerns about risk of bias for all studies, with evidence for most outcomes being of low certainty. In particular, valid and precise measures of behaviour were rarely used, and there were few instances of preregistered protocols and analysis plans, increasing the likelihood of selective outcome reporting.

CONCLUSIONS

In this study, we observed that feedback of medical images to individuals has the potential to motivate risk-reducing behaviours and reduce risk factors. Should this promise be corroborated through further adequately powered trials that better mitigate against risk of bias, such interventions could usefully capitalise upon the widespread and growing use of medical imaging technologies in healthcare.

The impact of pictorial health warnings on purchases of sugary drinks for children: A randomized controlled trial

BACKGROUND

Pictorial warnings on tobacco products are promising for motivating behavior change, but few studies have examined pictorial warnings for sugary drinks, especially in naturalistic environments. This study aimed to examine the impact of pictorial warnings on parents' purchases of sugary drinks for their children in a naturalistic store laboratory.

METHODS AND FINDINGS

Parents of children ages 2 to 12 (n = 325, 25% identifying as Black, 20% Hispanic) completed a shopping task in a naturalistic store laboratory in North Carolina. Participants were randomly assigned to a pictorial warnings arm (sugary drinks displayed pictorial health warnings about type 2 diabetes and heart damage) or a control arm (sugary drinks displayed a barcode label). Parents selected 1 beverage and 1 snack for their child, as well as 1 household good; one of these items was selected for them to purchase and take home. The primary outcome was whether parents purchased a sugary drink for their child. Secondary outcomes included reactions to the trial labels, attitudes toward sugary drinks, and intentions to serve their child sugary drinks. Pictorial warnings led to a 17-percentage point reduction in purchases of sugary drinks (95% CI for reduction: 7% to 27%), with 45% of parents in the control arm buying a sugary drink for their child compared to 28% in the pictorial warning arm (p = 0.002). The impact of pictorial warnings on purchases did not differ by any of the 13 participant characteristics examined (e.g., race/ethnicity, income, education, and age of child). Pictorial warnings also led to lower calories (kcal), purchased from sugary drinks (82 kcal in the control arm versus 52 kcal in the pictorial warnings arm, p = 0.003). Moreover, pictorial warnings led to lower intentions to serve sugary drinks to their child, feeling more in control of healthy eating decisions, greater thinking about the harms of sugary drinks, stronger negative emotional reactions, greater anticipated social interactions, lower perceived healthfulness of sugary drinks for their child, and greater injunctive norms to limit sugary drinks for their child (all p < 0.05). There was no evidence of difference between trial arms on noticing of the labels, appeal of sugary drinks, perceived amount of added sugar in sugary drinks, risk perceptions, or perceived tastiness of sugary drinks (all p > 0.05).

CONCLUSIONS

Pictorial warnings reduced parents' purchases of sugary drinks for their children in this naturalistic trial. Warnings on sugary drinks are a promising policy approach to reduce sugary drink purchasing in the US.

TRIAL REGISTRATION

The trial design, measures, power calculation, and analytic plan were registered before data collection at www.clinicaltrials.gov NCT04223687.

Public Health Messaging during the COVID-19 Pandemic and Beyond: Lessons from Communication Science

The COVID-19 pandemic has made it clear that effective public health messaging is an indispensable component of a robust pandemic response system. In this article, we review decades of research from the interdisciplinary field of communication science and provide evidence-based recommendations for COVID-19 public health messaging. We take a principled approach by systematically examining the communication process, focusing on decisions about what to say in a message (i.e., message content) and how to say it (i.e., message executions), and how these decisions impact message persuasiveness. Following a synthesis of each major line of literature, we discuss how science-based principles of message design can be used in COVID-19 public health messaging. Additionally, we identify emerging challenges for public health messaging during the COVID-19 pandemic and discuss possible remedies. We conclude that communication science offers promising public health messaging strategies for combatting COVID-19 and future pandemics.

Experimental study of front-of-package nutrition labels' efficacy on perceived healthfulness of sugar-sweetened beverages among youth in six countries

Front-of-package (FOP) nutrition labels have been proposed as a strategy to help limit sugar-sweetened beverage (SSB) consumption among youth. However, few studies have examined the efficacy of FOP labels in youth across different countries. A between-group experiment was conducted to examine the impact of FOP labels (no-label control, Health Star Rating, 'High in' Octagon, Guideline Daily Amount (GDA), Traffic Light, or Nutri-Score) on perceived healthfulness of an SSB. The study was conducted online in November-December 2019 with 10,762 children aged 10-17 from six countries: Australia, Canada, Chile, Mexico, the United Kingdom, and the United States. A binary logistic regression model tested the impacts of FOP label condition, country, and sociodemographic characteristics on participants' likelihood of perceiving the SSB to be Unhealthy. Compared to the control condition, participants in each of the five FOP label conditions were significantly more likely to perceive the SSB as Unhealthy (p < 0.002). The 'High in' Octagon label had the greatest impact on perceived healthfulness across five out of six countries, whereas the GDA and Nutri-Score labels demonstrated the lowest impact across all six countries. The impact of FOP labels was consistent across sex, age, race/ethnicity, and perceived income adequacy. FOP labels can significantly reduce the perceived healthfulness of SSBs among youth across multiple countries. The current study adds to the evidence that 'high in' labels, which use intuitive symbols such as the octagon 'stop sign', are the most efficacious labels for helping consumers identify foods high in nutrients of concern, including SSBs.

Health warning labels and alcohol selection: a randomised controlled experiment in a naturalistic shopping laboratory

BACKGROUND AND AIMS

Health warning labels (HWLs) on tobacco products reduce smoking. There is an absence of evidence concerning the impact of alcohol HWLs on selection or purchasing in naturalistic settings. Using a commercial-standard naturalistic shopping laboratory, this study aimed to estimate the impact on selection of alcoholic drinks of HWLs describing adverse health consequences of excessive alcohol consumption.

DESIGN

A between-subjects randomised experiment with three groups was conducted: group 1: image-and-text HWL; group 2: text-only HWL; group 3: no HWL.

SETTING

A commercial-standard naturalistic shopping laboratory in the United Kingdom.

PARTICIPANTS

Adults (n = 399, 55% female) over the age of 18 years, who purchased beer or wine weekly to drink at home.

INTERVENTIONS

Participants were randomised to one of three groups varying in the HWL displayed on the packaging of the alcoholic drinks: (i) image-and-text HWL (n = 135); (ii) text-only HWL (n = 129); (iii) no HWL (n = 135). Participants completed a shopping task, selecting items from a range of alcoholic and non-alcoholic drinks, and snacks.

MEASUREMENT

The primary outcome was the proportion of alcoholic drinks selected. Secondary outcomes included HWL ratings on negative emotional arousal and label acceptability.

FINDINGS

There was no clear evidence of a difference in the HWL groups for the percentage of drinks selected that were alcoholic compared to no HWL (44%): image-and-text HWL: 46% (odds ratio [OR] = 1.08, 95% confidence interval [CI] = 0.82, 1.42); text-only HWL: 41% (OR = 0.87, 95% CI = 0.67, 1.14). Concordant with there being no difference between groups, there was extreme evidence in favour of the null hypothesis (Bayes factor [BF] < 0.01). Negative emotional arousal was higher (P < 0.001) and acceptability lower (P < 0.001) in the image-and-text HWL group, compared to the text-only HWL group.

CONCLUSIONS

In a naturalistic shopping laboratory, there was no evidence that health warning labels describing the adverse health consequences of excessive alcohol consumption changed selection behaviour.

Nature and Potential Impact of Alcohol Health Warning Labels: A Scoping Review

Alcohol is toxic to human health. In addition to providing nutritional information, labels on alcohol products can be used to communicate warnings on alcohol-related harms to consumers. This scoping review examined novel or enhanced health warning labels to assess the current state of the research and the key studied characteristics of labels, along with their impact on the studied outcomes. Four databases (Web of Science, MEDLINE, PsycInfo, CINAHL) were searched between January 2010 and April 2021, and 27 papers were included in the review. The results found that most studies were undertaken in English-speaking populations, with the majority conducted online or in the laboratory setting as opposed to the real world. Seventy percent of the papers included at least one cancer-related message, in most instances referring either to cancer in general or to bowel cancer. Evidence from the only real-world long-term labelling intervention demonstrated that alcohol health warning labels designed to be visible and contain novel and specific information have the potential to be part of an effective labelling strategy. Alcohol health warning labels should be seen as tools to raise awareness on alcohol-related risks, being part of wider alcohol policy approaches.

'Joining the Dots': Individual, Sociocultural and Environmental Links between Alcohol Consumption, Dietary Intake and Body Weight-A Narrative Review

Alcohol is energy-dense, elicits weak satiety responses relative to solid food, inhibits dietary fat oxidation, and may stimulate food intake. It has, therefore, been proposed as a contributor to weight gain and obesity. The aim of this narrative review was to consolidate and critically appraise the evidence on the relationship of alcohol consumption with dietary intake and body weight, within mainstream (non-treatment) populations. Publications were identified from a PubMed keyword search using the terms 'alcohol', 'food', 'eating', 'weight', 'body mass index', 'obesity', 'food reward', 'inhibition', 'attentional bias', 'appetite', 'culture', 'social'. A snowball method and citation searches were used to identify additional relevant publications. Reference lists of relevant publications were also consulted. While limited by statistical heterogeneity, pooled results of experimental studies showed a relatively robust association between acute alcohol intake and greater food and total energy intake. This appears to occur via metabolic and psychological mechanisms that have not yet been fully elucidated. Evidence on the relationship between alcohol intake and weight is equivocal. Most evidence was derived from cross-sectional survey data which does not allow for a cause-effect relationship to be established. Observational research evidence was limited by heterogeneity and methodological issues, reducing the certainty of the evidence. We found very little qualitative work regarding the social, cultural, and environmental links between concurrent alcohol intake and eating behaviours. That the evidence of alcohol intake and body weight remains uncertain despite no shortage of research over the years, indicates that more innovative research methodologies and nuanced analyses are needed to capture what is clearly a complex and dynamic relationship. Also, given synergies between 'Big Food' and 'Big Alcohol' industries, effective policy solutions are likely to overlap and a unified approach to policy change may be more effective than isolated efforts. However, joint action may not occur until stronger evidence on the relationship between alcohol intake, food intake and weight is established.

Using a Naturalistic Store Laboratory for Clinical Trials of Point-of-Sale Nutrition Policies and Interventions: A Feasibility and Validation Study

Point-of-sale policies such as warnings and taxes are promising tools for improving the nutritional quality of food purchases. Research studies conducted in naturalistic store laboratories could improve the quality of evidence about point-of-sale interventions by allowing for realistic exposure in a controlled setting. This study aimed to assess whether purchasing behavior in a naturalistic store laboratory setting was similar to real-life purchasing behavior and to evaluate participants’ perceptions of store realism and the acceptability of research study protocols in this setting. In a longitudinal observational study in 2019, Latinx parents in North Carolina (n = 61) attended five weekly visits at the UNC Mini Mart, a naturalistic store laboratory that resembled a small convenience store. At each visit, participants purchased a week’s supply of beverages. Purchases of beverages in the Mini Mart were compared to participants’ purchases from receipts submitted the week prior to the study. Analyses compared the percentage of participants buying sugary drinks and non-sugary drinks in the Mini Mart vs. in real stores using Chi-Square tests with Fisher’s p. The percentage of parents who purchased sugary drinks in the Mini Mart (93%) was not significantly different from the percentage who purchased sugary drinks during the week before the study (74%, p = 0.28). The percentage purchasing non-sugary drinks was similar in the two settings (85% in the Mini Mart vs. 85% from receipts, p = 0.33). Nearly all participants reported that their Mini Mart purchases were similar to real-life purchases (96%); the Mini Mart felt like a real store (94%); they could find all the beverages they were looking for (92%); and they could imagine doing their real-life beverage shopping in the Mini Mart (92%). Moreover, retention was high, with 97% of participants attending the final study visit. These results indicate that naturalistic store laboratories are a promising method for increasing the ecological validity of trials to evaluate point-of-sale interventions.

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.

The effect of messaging on the acceptance of swaps to reduce the energy content of snacks and non-alcoholic drinks ordered in an experimental online workplace canteen: A randomised controlled trial

Finding effective ways to increase acceptance of lower-energy swaps offered for snacks and non-alcoholic drinks may reduce population energy intake. We examined whether incrementally increasing the tangibility of information accompanying swaps offered increased their acceptance. UK adults (n = 3481) selected a sweet snack, a savoury snack, and a drink in an experimental online canteen after being equally randomised to receive one of four messages when swaps were offered; a control message providing no specific information, a vague calorie message, an exact numeric-calories message or, a physical activity calorie equivalent (PACE). Primary outcomes were the between-group differences in (i) the odds that a sweet, savoury, or drink swap would be accepted and (ii) the energy content for each type of item ordered. Compared with control, the numeric-calories and PACE messages significantly increased the odds of accepting a sweet snack swap. All interventions significantly increased the odds of accepting savoury swaps compared with control. Only the PACE message significantly increased the odds of drink swap acceptance. The numeric-calories and PACE messages significantly reduced the energy content of sweet snacks. All interventions significantly reduced the energy content of savoury snacks. None of the intervention messages significantly reduced the energy content of drinks compared with control. Increasing the tangibility of information provided when offering swaps increased swap acceptance. PACE messaging was the most promising.

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.

Advancing Visual Health Communication Research to Improve Infodemic Response

During public health crises like the ongoing novel coronavirus pandemic, there is a need to amplify and improve critical health communication messages. This need is due to pandemics producing infodemic conditions, meaning the public information environment is oversaturated with information of questionable accuracy and utility. The strategic use of visuals can be leveraged to improve the quality of health communication during public health crises and lessen the unintended effects of infodemic conditions. In this essay, we review previous visual communication theorizing and research that provide insights for effective and efficient use of graphical (e.g., data visualizations) and illustrative (e.g., photos, illustrations, and content features) visuals. We also discuss and advocate for more systematic research on visual misinformation and visual narratives, as there are significant gaps in the literature about how people interpret, act on, and engage with these visual content types. More systematic research about these areas of visual health communication research will improve public communication during future public health crises.

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.