Interventions targeting conscious determinants of human behaviour to reduce the demand for meat: a systematic review with qualitative comparative analysis

Effects of increasing the availability of vegetarian options on main meal choices, meal offer satisfaction and liking: a pre-post analysis in a French university cafeteria

BACKGROUND

Changing the food environment is an important public health lever for encouraging sustainable food choices. Targeting the availability of vegetarian main meals served in cafeterias substantially affects food choice, but acceptability has never been assessed. We examined the effects of an availability intervention at a French university cafeteria on students' main meal choices, meal offer satisfaction and liking.

METHODS

A four-week controlled trial was conducted in a university cafeteria in Dijon, France. During the two-week control period, vegetarian main meals constituted 24% of the offer. In the subsequent two-week intervention period, this proportion increased to 48%, while all the other menu items remained unchanged. Students were not informed of the change. Student choices were tracked using production data, and daily paper ballots were used to assess student satisfaction with the meal offer and liking of the main meal they chose (score range [1;5]). Nutritional quality, environmental impact, and cost of production of meal choices were calculated for each lunchtime. Food waste was measured over 4 lunchtimes during control and intervention periods. An online questionnaire collected student feedback at the end of the study.

RESULTS

Doubling availability of vegetarian main meals significantly increased the likelihood of choosing vegetarian options (OR = 2.57, 95% CI = [2.41; 2.74]). Responses of the paper ballots (n = 18,342) indicated slight improvements in meal offer satisfaction from 4.05 ± 0.92 to 4.07 ± 0.93 (p = 0.028) and in liking from 4.09 ± 0.90 to 4.13 ± 0.92 (p < 0.001) during control and intervention periods, respectively. The end-of-study questionnaire (n = 510) revealed that only 6% of students noticed a change the availability of vegetarian main meals. The intervention led to a decrease in the environmental impact of the main meals chosen, a slight decrease in nutritional quality, a slight increase in meal costs and no change in food waste.

CONCLUSIONS

Doubling availability of vegetarian main meals in a university cafeteria resulted in a twofold increase in their selection, with students reporting being more satisfied and liking the main meals more during the intervention period. These results suggest that serving an equal proportion of vegetarian and nonvegetarian main meals could be considered in French university cafeterias to tackle environmental issues.

TRIAL REGISTRATION

Study protocol and analysis plan were pre-registered on the Open Science Framework ( https://osf.io/pf3x7/ ).

What factors influence sustainable and healthy diet consumption? A review and synthesis of literature within the university setting and beyond

Globally, typical dietary patterns are neither healthy nor sustainable. Recognizing the key role of dietary change in reducing noncommunicable disease risk and addressing environmental degradation, it is crucial to understand how to shift individuals toward a sustainable and healthy diet (SHD). In this literature review, we introduced the concept of a SHD and outlined the dietary behaviors necessary to transition toward SHD consumption; we reviewed the literature on factors that may influence sustainable (and unsustainable) dietary behaviors in adults; and we developed a novel scoring system to rank factors by priority for targeting in future research. Given the significant potential to promote a sustainable and healthy dietary transition on the university campus-where factors that may impact dietary behaviors can be targeted at all levels of influence (i.e., individual, interpersonal, environmental, policy)-we narrowed our focus to this setting throughout. Aided by our novel scoring system, we identified conscious habitual eating, product price, food availability/accessibility, product convenience, self-regulation skills, knowledge of animal ethics/welfare, food promotion, and eating norms as important modifiable factors that may influence university students' dietary behaviors. When scored without consideration for the university population, these factors were also ranked as highest priority, as was modified portion sizes. Our findings offer insight into factors that may warrant attention in future research aimed at promoting SHDs. In particular, the high-priority factors identified from our synthesis of the literature could help guide the development of more personalized dietary behavioral interventions within the university setting and beyond.

Nudging plant-based alternatives to meat and dairy in a real-life online supermarket: A randomized controlled trial

A shift from predominantly animal-based to plant-based consumption can benefit both planetary and public health. Nudging may help to promote such a shift. This study investigated nudge effects on plant-based alternatives to meat and dairy in an online supermarket. We conducted a two-arm, parallel-group, randomized controlled real-life online supermarket trial. Each customer transaction was randomized to a control arm (regular online supermarket) or an intervention arm (addition of placement, hedonic property and dynamic social norm nudges promoting meat and dairy alternatives). Outcomes were the aggregate of meat and dairy alternative purchases (primary outcome), the number of meat purchases, dairy purchases, meat alternative purchases, and dairy alternative purchases (secondary), and retailer revenue (tertiary). Generalized linear mixed models with a Conway-Maxwell Poisson distribution were used to estimate incidence rate ratios (IRRs). Analyzed data included 8488 transactions by participants (n = 4,266 control arm, n = 4,222 intervention arm), out of which 2,411 (66%) were aged above 45 years, 5,660 (67%) were females, and 1,970 (23%) lived in socially disadvantaged neighborhoods. Intervention arm participants purchased 10% (IRR 1.10 (95% CI 0.99-1.23)) more meat and dairy alternatives and 16% (1.16 (0.99-1.36)) more meat alternatives than control arm participants, although these findings are not statistically significant. There was no difference in dairy alternative purchases (1.00 (0.90-1.10)). Intervention arm participants purchased 3% less meats (0.97 (0.93-1.02)) and 2% less dairy products (0.98 (0.95-1.02)) than control participants. Retailer revenue was not affected (0.98 (0.95-1.01)). Online nudging strategies alone did not lead to a statistically significant higher amount of plant-based purchases, but replication of this work is needed with increased study power. Future studies should also consider nudging strategies as part of a broader set of policies to promote plant-based purchases. TRIAL REGISTRATION: Prospectively registered on 14th of May 2022. ISRCTN16569242 (https://doi.org/10.1186/ISRCTN16569242).

Moderate low-cost modifications in diet prevent a substantial number of deaths and mitigate environmental impacts in Brazil

PURPOSE

This study aimed to estimate the health, economic, and environmental impacts of moderate simulated interventions on dietary intake in Brazil.

METHODS

Data on food price and consumption were obtained from three nationwide surveys. Baseline dietary intake was estimated for 33,859 individuals aged 25 years and older. Counterfactual intakes were based on six hypothetical intervention scenarios, by changing the weekly frequency and serving size in low or high consumers of fruit and vegetables (FV), milk, whole grains, red and processed meats, and sugar-sweetened beverages. For each scenario, we estimated the attributable number of deaths and disability-adjusted life years (DALY), monetary cost, environmental impacts (14 midpoint indicators), and environmentally-mediated health impacts.

RESULTS

Compared with the baseline intake and cost, the most expensive intervention (+ 8.3%) was to increase FV intake (+ 125 g), resulting in a 1.2% reduction in all-cause mortality (16,307 deaths/year). The cheapest (- 9.9%) was to reduce red and processed meat intake (- 40 g), resulting in a 1.1% reduction in all-cause mortality (14,272 deaths/year). The combined intervention was, on average, 3.7% cheaper than the baseline cost, resulting in an increase in diet cost for 30% of the population (45-22% in the lower- and higher-income groups); all-cause mortality would be reduced by 3.8% (49,488 deaths/year). Interventions targeting red and processed meats would reduce emissions and resource use by 35-55%, in addition to reducing 2300 DALYs/year.

CONCLUSION

A meaningful number of deaths can be avoided and environmental impacts reduced through moderate and potentially affordable diet modifications.

Transitioning towards more plant-based diets: sharing expert knowledge through a system lens

Transitioning towards more plant-based protein diets is essential for public and planetary health. Current research about consumption practices of protein sources provides limited insight in the multidisciplinary nature and interconnectivity of the food environment. This study aimed to collect mental models of review authors by synthesizing both their implicit and explicit system views into an overarching system view. Published reviews were used to select participants and identify variables that explain the protein transition in relation to the food environment. To overcome differences in disciplines and scale levels (e.g. individual, interpersonal, environmental), variables were organized according to the Determinants of Nutrition and Eating Framework. Eight review authors shared their mental models in an interview. Participants were asked to construct a causal loop diagram (CLD), a tool proven valuable in making one's ontology explicit to others. Implicit system views in narrative were converted into CLDs using a coding framework. The overarching system view suggests that a multitude of feedback loops sustain current consumption patterns of protein sources, for example by reinforcement through habit, availability and peer support. Several aspects require further research, such as variable relationships that were subject to disagreement and the lack of reciprocity between the physical and social elements of the food environment. In addition, knowledge gaps were exposed, including long-term behaviour and interaction of multiple variables. As a boundary object, the overarching system view can facilitate the direction of future research. The findings underscore the interconnected nature of many disparate elements within the food environment, stressing the need for holistic methods like systems thinking. These are essential in developing a systemic understanding and facilitating the transition towards more plant-based diets.

The perceptions of food service staff in a nursing home on an upcoming transition towards a healthy and sustainable food environment: a qualitative study

BACKGROUND

Healthy and sustainable food environments are urgently needed, also in nursing and residential care homes. Malnutrition in care homes is becoming an increasing problem as populations worldwide are ageing and many older people do not consume sufficient protein, fibre, fruit, and vegetables. Nursing homes also often experience a lot of food waste. A transition in the food environment like a nursing home, involves the participation of facility management and food service staff members. This study aims to map out their perceived barriers and facilitators for this transition.

METHODS

A qualitative study using semi-structured interviews was conducted with food service staff members (n = 16), comprising of kitchen staff (n = 4), wait staff (n = 10), and facility management (n = 2) of two nursing homes in the Netherlands. Thematic analysis was used to derive content and meaning from transcribed interviews.

RESULTS

Four main themes were identified. Theme 1: 'Communication, transparency and accountability in the chain', highlighting the lack of effective communication flows and a fragmented overview of the food service chain as a whole. Theme 2: 'Understanding, knowledge and ability of the concepts healthy and sustainable', revealing the gap in staff's understanding of these abstract concepts, despite perceiving themselves as having sufficient knowledge and ability. Theme 3: 'The pampering service mind-set', highlighting the contradiction in the staff's shared goal of proving the highest quality of life for residents while also pampering them in ways that may not align with promoting healthy and sustainable food choices. Theme 4: 'Transition is important but hard to realize', describing the barriers such as existing routines and a lack of resources as challenges to implementing changes in the food service.

CONCLUSIONS

Facilitators to transitioning nursing homes towards a healthy and sustainable food environment as perceived by staff members included transparent communication, accountability in the food supply chain, staff's perceived ability and shared goal, while barriers included lack of understanding of the concepts healthy and sustainable, the current pampering mindset, and top-down decision-making. These findings provide valuable insights for nursing homes seeking to transition towards a healthier and more sustainable food environment.

Feeling morally troubled about meat, dairy, egg, and fish consumption: Dissonance reduction strategies among different dietary groups

A largescale shift towards plant-based diets is considered a critical requirement for tackling ethical, environmental, and global health issues associated with animal food production and consumption. Although previous research has identified psychological strategies that enable meat-eaters to justify and continue meat consumption and feel less morally conflicted about it, research on the psychological strategies that enable consumers to continue dairy, egg, and fish consumption is scarce. We conducted an online survey study using an adjusted version of the Meat-Eating Justification Scale to investigate the use of psychological strategies to cope with cognitive dissonance related to meat, dairy, egg, and fish consumption in omnivores (n = 186), pescatarians (n = 106), vegetarians (n = 143), vegans (n = 203), and flexitarians (n = 63). Results indicated greater use of meat-related dissonance reduction strategies among omnivores as compared to other dietary groups, greater use of fish-related dissonance reduction strategies among fish consumers (omnivores, flexitarians and pescatarians) compared to vegetarians and vegans, and greater use of dairy and egg-related dissonance reduction strategies among dairy and egg consumers (omnivores, flexitarians, pescatarians, and vegetarians) as compared to vegans. This pattern was particularly clear for justifications used to defend animal product consumption, denial of animal suffering, and use of dichotomization when considering meat and fish consumption. These findings highlight the importance of extending the research on dissonance reduction strategies beyond meat consumption and studying the consumption of a range of animal products. This can help in identifying the psychological barriers to adopting a plant-based diet and informing interventions for behaviour change.

Too Close to Eat? Solidarity with Animals, Animal Welfare and Antibiotic Use

Meat consumption is influenced by a variety of factors including feelings of affinity towards farm animals. The goal of this study was to examine the relationship between solidarity with animals, attitudes towards the treatment of animals and antibiotics use in livestock, and pork  consumption. Data were drawn from a sample of 265 respondents in the US. Correlation and mediation analyses were performed. The results indicate a moderate but positive correlation between solidarity with animals and proecological beliefs. The association between attitudes towards the treatment of farm animals, aspects of the attitudes towards antibiotic use and solidarity with animals was also positive. We also find  that proecological beliefs and concerns about the treatment of farm animals negatively influenced consumption. The effect of attitudes towards antibiotic use and solidarity with animals on consumption were however fully mediated by proecological beliefs. The results suggest that social identification with animals can play a significant role in food choice. However, its effect is part of a broader connection to nature. Holistic approaches are therefore required to address livestock production practices that may be considered unnatural.

Demographic and Socioeconomic Correlates of Disproportionate Beef Consumption among US Adults in an Age of Global Warming

Concern for the environment when making dietary choices has grown as the contribution of the food sector to global greenhouse gas emissions becomes more widely known. Understanding the correlates of beef eating could assist in the targeting of campaigns to reduce the consumption of high-impact foods. The objective of this study was to identify the demographic, socioeconomic, and behavioral correlates of disproportionate beef consumption in the United States. We analyzed 24-h dietary recall data from adults (n = 10,248) in the 2015-2018 National Health and Nutrition Examination Survey (NHANES). Disproportionate beef consumption was defined as an intake greater than four ounce-equivalents per 2200 kcal. Associations of this indicator variable with gender, age, race/ethnicity, education, family income, diet knowledge, and away-from-home meals were assessed using logistic regression, incorporating survey design and weighting. Disproportionate beef diets were consumed by 12% of individuals, but accounted for half of all beef consumed. Males were more likely than females (p < 0.001) to consume these diets. This relationship was seen in all bivariate and multivariable models. Older adults, college graduates, and those who looked up the MyPlate educational campaign online were less likely (p < 0.01) to consume a disproportionate beef diet. While almost one-third of reported consumption came from cuts of beef (e.g., steak or brisket), six of the top ten beef sources were mixed dishes: burgers, meat mixed dishes, burritos and tacos, frankfurters, soups, and pasta. Efforts to address climate change through diet modification could benefit from targeting campaigns to the highest consumers of beef, as their consumption accounts for half of all beef consumed.

Vegans, vegetarians, fish-eaters and meat-eaters in the UK show discrepant environmental impacts

Modelled dietary scenarios often fail to reflect true dietary practice and do not account for variation in the environmental burden of food due to sourcing and production methods. Here we link dietary data from a sample of 55,504 vegans, vegetarians, fish-eaters and meat-eaters with food-level data on greenhouse gas emissions, land use, water use, eutrophication risk and potential biodiversity loss from a review of 570 life-cycle assessments covering more than 38,000 farms in 119 countries. Our results include the variation in food production and sourcing that is observed in the review of life-cycle assessments. All environmental indicators showed a positive association with amounts of animal-based food consumed. Dietary impacts of vegans were 25.1% (95% uncertainty interval, 15.1-37.0%) of high meat-eaters (≥100 g total meat consumed per day) for greenhouse gas emissions, 25.1% (7.1-44.5%) for land use, 46.4% (21.0-81.0%) for water use, 27.0% (19.4-40.4%) for eutrophication and 34.3% (12.0-65.3%) for biodiversity. At least 30% differences were found between low and high meat-eaters for most indicators. Despite substantial variation due to where and how food is produced, the relationship between environmental impact and animal-based food consumption is clear and should prompt the reduction of the latter.

Why don't politicians talk about meat? The political psychology of human-animal relations in elections

Building on literature from political science and psychology, I argue that political attention on animals and animal-friendly political candidates cause voter backlash. I test this using two different kinds of experiments with large, representative samples. I ask respondents to consider political candidates running for office in a U.S. presidential primary context. I find that, overall, political attention on the need to reduce meat consumption for environmental reasons caused voter backlash compared to both a control condition and attention on the need to reduce reliance on gasoline-powered vehicles (also for environmental reasons). But, the heterogeneous effects of partisan identification were strong: voter backlash was mainly driven by Republicans and Democrats were neutral. Surprisingly, candidates who put attention on farm animal rights during elections faced no voter backlash from Republicans or Democrats. Animal-friendly candidates, particularly Black women and Latinas, with attributes that demonstrate personal concern for farm animals and strong support for animal rights generally fared very well in elections, receiving large boosts in voter support. This work launches a research agenda in political psychology that "brings the animal in" to politics.

Strategies for reducing meat consumption within college and university settings: A systematic review and meta-analysis

Introduction

Despite the considerable public and planetary health benefits associated with reducing the amount of meat consumed in high-income countries, there is a limited empirical understanding of how these voluntary changes in food choice can be effectively facilitated across different settings. While prior reviews have given us broad insights into the varying capacities of behavior change strategies to promote meaningful reductions in meat consumption, none have compared how they perform relative to each other within a uniform dining context.

Methods

To address this gap in the literature, we synthesized the available research on university-implemented meat reduction interventions and examined the variations in the success rates and effect estimates associated with each of the three approaches identified in our systematic review.

Results

From our analyses of the 31 studies that met our criteria for inclusion (n = 31), we found that most were successful in reducing the amount of meat consumed within university settings. Moreover, independent of the number of individual strategies being used, multimodal interventions were found to be more reliable and effective in facilitating these changes in food choice than interventions targeting the choice architecture of the retail environment or conscious decision-making processes alone.

Discussion

In addition to demonstrating the overall value of behavior change initiatives in advancing more sustainable dining practices on college and university campuses, this study lends further insights into the merits and mechanics underlying strategically integrated approaches to dietary change. Further investigations exploring the persistence and generalizability of these effects and intervention design principles are needed.

Systematic review registration

https://doi.org/10.17605/OSF.IO/DXQ5V, identifier: 10.17605/OSF.IO/DXQ5V.

Low-cost climate-change informational intervention reduces meat consumption among students for 3 years

Evidence on the impact of information campaigns on meat consumption patterns is limited. Here, using a dataset of more than 100,000 meal selections over 3 years, we examine the long-term effects of an informational intervention designed to increase awareness about the role of meat consumption in climate change. Students randomized to the treatment group reduced their meat consumption by 5.6 percentage points with no signs of reversal over 3 years. Calculations indicate a high return on investment even under conservative assumptions (~US$14 per metric ton CO₂eq). Our findings show that informational interventions can be cost effective and generate long-lasting shifts towards more sustainable food options.

Culturally-tailored cookbook for promoting positive dietary change among hypertensive Filipino Americans: a pilot study

Introduction

Among all Asian American subgroups, Filipino-Americans have consistently been shown to have the highest rates of hypertension, raising risks of heart attack and stroke. Despite this alarming fact, little has been done to investigate culturally-sensitive interventions to control hypertension rates in this vulnerable population. To address the lack of culturally-relevant lifestyle options for blood pressure management currently available to the Filipino community, this exploratory pilot study used a design thinking approach informed by culinary medicine to develop a culturally-tailored, heart-healthy, and low sodium recipe cookbook for Filipino Americans with hypertension and evaluate its feasibility as a hypertension intervention.

Methods

Our team developed a cookbook using participatory methods and design thinking, utilizing input from five Filipino culinary experts and a Registered Dietitian. The cookbook incorporates traditional Filipino recipes, excerpts from community members' interviews, and nutrient analyses. Twenty Filipinx-identifying individuals* who self-reported physician-diagnosed hypertension were recruited from Filipino community-based organizations, enrolled into this study, provided with the cookbook, and asked to cook at least one recipe. Pre- and post-intervention surveys were conducted and centered around behavior change and features of the cookbook.

Results

This study provided evidence for the cookbook's acceptability and feasibility, with participants' open-ended responses revealing that the recipes, nutrition labels, illustrations, and cultural aspects of the cookbook increased motivation to achieve dietary change, including reducing sodium in their diet to improve their blood pressure. Participant responses also indicated positive behavior change as a result of using the cookbook, with participants reporting increased likelihood of adopting recommended actions to lower their BP after utilizing the cookbook ( x ¯ = 80.83%), compared to before ( x ¯ = 63.75%, p < 0.008), according to Hypertension Self-Care Management scaled scores.

Discussion

In conclusion, the results of this pilot study demonstrated acceptability of this unique cookbook and provide preliminary findings consistent with increased motivation in participants to make dietary changes and improve personal health, drawing attention to the importance of considering future culturally-tailored health interventions. Next steps should include a robust, randomized controlled trial design comparing measured blood pressure outcomes of an intervention vs. control group. *Filipinx is an inclusive term representing the gender identities of all participants in our study.

Evaluation of OPTIMISE (Online Programme to Tackle Individual's Meat Intake Through Self-regulation): Cohort Study

BACKGROUND

There is an urgent need to reduce society's meat consumption to help mitigate climate change and reduce noncommunicable diseases.

OBJECTIVE

This study aimed to investigate changes in meat intake after participation in an online, multicomponent, self-regulation intervention.

METHODS

We conducted a pre-post observational study among adult meat eaters in the United Kingdom who signed up to a website offering support based on self-regulation theory to reduce meat consumption. The program lasted 9 weeks (including a 1-week baseline phase, a 4-week active intervention phase, and a 4-week maintenance phase), comprising self-monitoring, goal setting, action planning, and health and environmental feedback. Meat intake was estimated during weeks 1, 5, and 9 using a 7-day meat frequency questionnaire. We analyzed the change in mean daily meat intake from baseline to week 5 and week 9 among those reporting data using a hierarchical linear mixed model. We assessed changes in attitudes toward meat consumption by questionnaire and considered the acceptability and feasibility of the intervention.

RESULTS

The baseline cohort consisted of 289 participants, of whom 77 were analyzed at week 5 (26.6% of the baseline sample) and 55 at week 9 (71.4% of the week 5 sample). We observed large reductions in meat intake at 5 and 9 weeks: -57 (95% CI -70 to -43) g/day (P<.001) and -49 (95% CI -64 to -34) g/day (P<.001), respectively. Participants' meat-free self-efficacy increased, meat-eating identities moved toward reduced-meat and non-meat-eating identities, and perceptions of meat consumption as the social norm reduced. Participants who completed the study reported high engagement and satisfaction with the intervention.

CONCLUSIONS

Among people motivated to engage, this online self-regulation program may lead to large reductions in meat intake for more than 2 months, with promising signs of a change in meat-eating identity toward more plant-based diets. This digital behavior change intervention could be offered to complement population-level interventions to support reduction of meat consumption.

Ideological resistance to veg*n advocacy: An identity-based motivational account

Animal-based diets in Western countries are increasingly regarded as unsustainable because of their impact on human health, environmental and animal welfare. Promoting shifts toward more plant-based diets seems an effective way to avoid these harms in practice. Nevertheless, claims against the consumption of animal products contradict the ideology of the omnivorous majority known as carnism. Carnism supports animal-product consumption as a cherished social habit that is harmless and unavoidable and invalidates minorities with plant-based diets: vegetarians and vegans (veg*ns). In this theoretical review, we integrate socio-psychological and empirical literature to provide an identity-based motivational account of ideological resistance to veg*n advocacy. Advocates who argue against the consumption of animal products often make claims that it is harmful, and avoidable by making dietary changes toward veg*n diets. In response, omnivores are likely to experience a simultaneous threat to their moral identity and their identity as consumer of animal products, which may arouse motivations to rationalize animal-product consumption and to obscure harms. If omnivores engage in such motivated reasoning and motivated ignorance, this may also inform negative stereotyping and stigmatization of veg*n advocates. These "pro-carnist" and "counter-veg*n" defenses can be linked with various personal and social motivations to eat animal products (e.g., meat attachment, gender, speciesism) and reinforce commitment to and ambivalence about eating animal products. This does not mean, however, that veg*n advocates cannot exert any influence. An apparent resistance may mask indirect and private acceptance of advocates' claims, priming commitment to change behavior toward veg*n diets often at a later point in time. Based on our theoretical account, we provide directions for future research.

What do Consumers Read About Meat? An Analysis of Media Representations of the Meat-environment Relationship Found in Popular Online News Sites in the UK

Previous scholarship suggests that elite media have tended to pay little attention to the adverse environmental impacts associated with meat consumption and production. Through content analysis of 116 articles from 2019, published on eight popular online news sites consumed by a wide range of demographics in the UK, including lower-income groups (the sector most likely to eat meat), we identify common anti-meat and pro-meat environmental narratives, solutions and recommendations, and the dominant sentiment towards both meat consumption and production. We observed a significantly greater presence of anti-meat consumption and/or production narratives than pro-meat. Over half the articles showed anti-meat consumption sentiment, with only 5% predominately in favour. 10% were against unspecified or industrial production practices, 28% were against industrial-scale farming but supported sustainable methods; and none were entirely in favour of the meat industry. These findings are reflected in the dominant recommendation, present in over 60% of articles, to eat less meat. Our results add substantially to previous media research, particularly showing the increased volume of coverage of the meat-environment nexus, varying levels of contestation around meat eating, and the division of responsibility between consumers and industry.

Exploring young Australians' understanding of sustainable and healthy diets: a qualitative study

OBJECTIVE

This qualitative study aimed to explore young Australians' perspectives, motivators and current practices in achieving a sustainable and healthy diet.

DESIGN

Semi-structured online interviews were conducted with young Australians. Interviews were audio-recorded using the online Zoom platform, transcribed and analysed using a deductive analysis method by applying the Theoretical Domains Framework and inductive thematic data analysis.

SETTING

Young Australians recruited via social media platforms, noticeboard announcements and flyers.

SUBJECTS

Twenty-two Australians aged 18 to 25 years.

RESULTS

The majority of participants were aware of some aspects of a sustainable and healthy diet and indicated the need to reduce meat intake, increase intake of plant-based foods, reduce food wastage and packaging and reduce food miles. Young adults were motivated to adopt more sustainable dietary practices but reported that individual and environmental factors such as low food literacy, limited food preparation and cooking skills, lack of availability and accessibility of environmentally friendly food options and costs associated with sustainable and healthy diets hindered their ability to do so.

CONCLUSIONS

Given the barriers faced by many of our participants, there is a need for interventions aimed at improving food literacy and food preparation and cooking skills as well as those that create food environments that make it easy to select sustainable and healthy diets. Future research is needed for longitudinal larger scale quantitative studies to confirm our qualitative findings. In addition, the development and evaluation of individual and micro-environmental-based interventions promote sustainable and healthy diets more comprehensively.

Social Influence and Meat-Eating Behaviour

In recent years, interest in non-meat diets has been growing at an exponential rate in many countries. There is a wide consensus now that increased meat consumption is linked to higher health risks and environmental impact. Yet humans are social animals. Even the very personal decision of whether to eat meat or not is influenced by others around them. Using data from the British Social Attitude Survey, we develop an agent-based model to study the effect of social influence on the spread of meat-eating behaviour in the British population. We find that social influence is crucial in determining the spread of different meat-eating behaviours. According to the model, in order to bring about large-scale changes in meat-eating behaviours at the national level, people need to (1) have a strong openness to influences from others who have different meat-eating behaviour and (2) have a weak tendency to reinforce their current meat-eating behaviour after observing others in their own social group sharing the same behaviour.

Replacing meat with alternative plant-based products (RE-MAP): a randomized controlled trial of a multicomponent behavioral intervention to reduce meat consumption

BACKGROUND

Reducing meat consumption could protect the environment and human health.

OBJECTIVES

We tested the impact of a behavioral intervention to reduce meat consumption.

METHODS

Adult volunteers who regularly consumed meat were recruited from the general public and randomized 1:1 to an intervention or control condition. The intervention comprised free meat substitutes for 4 weeks, information about the benefits of eating less meat, success stories, and recipes. The control group received no intervention or advice on dietary change. The primary outcome was daily meat consumption after 4 weeks, assessed by a 7-day food diary, and repeated after 8 weeks as a secondary outcome. Other secondary and exploratory outcomes included the consumption of meat substitutes, cardiovascular risk factors, psychosocial variables related to meat consumption, and the nutritional composition of the diet. We also estimated the intervention's environmental impact. We evaluated the intervention using generalized linear mixed-effects models.

RESULTS

Between June 2018 and October 2019, 115 participants were randomized. The baseline meat consumption values were 134 g/d in the control group and 130 g/d in the intervention group. Relative to the control condition, the intervention reduced meat consumption at 4 weeks by 63 g/d (95% CI: 44-82; P < 0.0001; n = 114) and at 8 weeks by 39 g/d (95% CI: 16-62; P = 0.0009; n = 113), adjusting for sex and baseline consumption. The intervention significantly increased the consumption of meat substitutes without changing the intakes of other principal food groups. The intervention increased intentions, positive attitudes, perceived control, and subjective norms of eating a low-meat diet and using meat substitutes, and decreased attachment to meat. At 8 weeks, 55% of intervention recipients identified as meat eaters, compared to 89% of participants in the control group.

CONCLUSIONS

A behavioral program involving free meat substitutes can reduce meat intake and change psychosocial constructs consistent with a sustained reduction in meat intake.

Identifying effective interventions to promote consumption of protein-rich foods from lower ecological footprint sources: A systematic literature review

Addressing overconsumption of protein-rich foods from high ecological footprint sources can have positive impacts on health such as reduction of non-communicable disease risk and protecting the natural environment. With the increased attention towards development of ecologically sustainable diets, this systematic review aimed to critically review literature on effectiveness of those interventions aiming to promote protein-rich foods from lower ecological footprint sources. Five electronic databases (Medline, Web of Science, Scopus, Embase and Global Health) were searched for articles published up to January 2021. Quantitative studies were eligible for inclusion if they reported on actual or intended consumption of protein-rich animal-derived and/or plant-based foods; purchase, or selection of meat/plant-based diet in real or virtual environments. We assessed 140 full-text articles for eligibility of which 51 were included in this review. The results were narratively synthesised. Included studies were categorised into individual level behaviour change interventions (n = 33) which included education, counselling and self-monitoring, and micro-environmental/structural behaviour change interventions (n = 18) which included menu manipulation, choice architecture and multicomponent approaches. Half of individual level interventions (52%) aimed to reduce red/processed meat intake among people with current/past chronic conditions which reduced meat intake in the short term. The majority of micro-environmental studies focused on increasing plant-based diet in dining facilities, leading to positive dietary changes. These findings point to a clear gap in the current evidence base for interventions that promote plant-based diet in the general population.

Effectiveness of an Online Programme to Tackle Individual's Meat Intake through SElf-regulation (OPTIMISE): A randomised controlled trial

Purpose

A reduction in meat intake is recommended to meet health and environmental sustainability goals. This study aimed to evaluate the effectiveness of an online self-regulation intervention to reduce meat consumption.

Methods

One hundred and fifty one adult meat eaters were randomised 1:1 to a multi-component self-regulation intervention or an information-only control. The study lasted 9 weeks (1-week self-monitoring; 4-week active intervention; and 4-week maintenance phase). The intervention included goal-setting, self-monitoring, action-planning, and health and environmental feedback. Meat intake was estimated through daily questionnaires in weeks 1, 5 and 9. The primary outcome was change in meat consumption from baseline to five weeks. Secondary outcomes included change from baseline to nine weeks and change in red and processed meat intake. We used linear regression models to assess the effectiveness of all the above outcomes.

Results

Across the whole sample, meat intake was 226 g/day at baseline, 118 g/day at five weeks, and 114 g/day at nine weeks. At five weeks, the intervention led to a 40 g/day (95%CI − 11.6,− 67.5, P = 0.006) reduction in meat intake, including a 35 g/day (95%CI − 7.7, − 61.7, P = 0.012) reduction in red and processed meat, relative to control. There were no significant differences in meat reduction after the four-week maintenance phase (− 12 g/day intervention vs control, 95% CI 19.1, − 43.4, P = 0.443). Participants said the intervention was informative and eye-opening.

Conclusion

The intervention was popular among participants and helped achieve initial reductions in meat intake, but the longer-term reductions did not exceed control.

Trial registration

ClinicalTrials.gov NCT04961216, 14th July 2021, retrospectively registered.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-022-02828-9.

A Comparison of Dietary Patterns and Factors Influencing Food Choice among Ethnic Groups Living in One Locality: A Systematic Review

Globally, the number of minority ethnic groups in high-income countries is increasing. However, despite this demographic change, most national food consumption surveys are not representative of ethnically diverse populations. In consequence, many ethnic minorities' dietary intakes are underreported, meaning that accurate analysis of food intake and nutrient status among these groups is not possible. This systematic review aims to address these gaps and understand differences in dietary intakes and influencers of dietary habits of ethnic groups worldwide. A systematic search was conducted through three databases (Pubmed, Web of Science and Scopus) and manual searches, generating n = 56,647 results. A final search of these databases was completed on 13 September 2021, resulting in a total of 49 studies being included in this review. Overall, food group intakes-particularly fruit, vegetable and fish intake-and diet quality scores were seen to differ between ethnicities. Overall Black/African American groups were reported to be among the poorest consumers of fruit and vegetables, whilst Asian groups achieved high diet quality scores due to higher fish intakes and lower fat intakes compared to other groups. Limited data investigated how nutrient intakes, dietary and meal patterns compared between groups, meaning that not all aspects of dietary intake could be compared. Socioeconomic status and food availability appeared to be associated with food choice of ethnic groups, however, confounding factors should be considered more closely. Future work should focus on comparing nutrient intakes and meal patterns between ethnicities and investigate potential targeted interventions which may support adherence to food-based dietary guidelines by all ethnic groups.

Differences between Vegetarians and Omnivores in Food Choice Motivation and Dietarian Identity

Vegetarianism is on the rise worldwide and its importance is being emphasized in various ways, such as in its sustainability, environmental, food system, and ethical aspects. The purpose of the study is to identify motivations behind food choices and dietarian identity, to investigate the perceptions about plant-based foods, and to identify differences between vegetarians and omnivores. We conducted an online survey of 245 vegetarians and 246 omnivores. There was a significant difference between vegetarians and omnivores. In food choice motivations, vegetarians scored higher in the factors of ‘ethical concern’, ‘health’, and ‘convenience and price’, while omnivores responded higher in ‘sensory appeal’ and ‘weight control’ factors. In the dietarian identity, vegetarians scored higher in the ‘complex motivation’ and ‘strictness’ factors, while on the other hand omnivores scored higher in ‘out-group regard’ and ‘public regard’ factors. Although the reasons can be different, we confirmed that both vegetarians and omnivores are positive toward plant-based foods. Our results suggest that different strategies will be needed to promote plant-based food consumption to vegetarians and to omnivores.

Is Eating Less Meat Possible? Exploring the Willingness to Reduce Meat Consumption among Millennials Working in Polish Cities

Reducing the consumption of meat constitutes an important part of the global shift towards more sustainable food systems. At the same time, meat is firmly established in the food culture of most human beings, and better understanding of individual behaviors is essential to facilitate a durable change in contemporary eating patterns. To determine the level and nature of attachment to meat among consumers, the Meat Attachment Questionnaire (MAQ) in relation to the phases of behaviour change in the meat consumption reduction process was utilised. Data collected through a survey carried out among Poles aged 25–40 years living in cities were analysed with the use of Spearman’s correlations and one-way ANOVA with Tukey’s post-hoc tests. The biggest share of the studied group of millennials (N = 317) never considered reducing their meat consumption (Phase 1–41%) and was described by the highest level of MAQ score in all its categories: hedonism, affinity, dependence, and entitlement. More than half of the respondents in Phase 2 participants (“planners”) declared a willingness to cut down meat consumption but had not yet put their intentions into practice. Respondents qualified in Phase 3 declared the highest willingness to reduce meat consumption and were significantly less attached to meat regarding all MAQ categories than respondents in Phase 1. The 9% of the study participants (Phase 4) had already limited the frequency of their meat consumption to “several times a week”, this however still remains insufficient compared to the ambitious goals of sustainable healthy diets. Results indicated that meat attachment categories, especially hedonism and dependence, were identified as predictors of willingness to reduce meat consumption. Research exploring the determinants of change and possibilities of effective communication about meat reduction on an individual level in different cultural settings are needed.

Effectiveness of a Theory-Informed Documentary to Reduce Consumption of Meat and Animal Products: Three Randomized Controlled Experiments

Several societal issues could be mitigated by reducing global consumption of meat and animal products (MAP). In three randomized, controlled experiments (n=217 to 574), we evaluated the effects of a documentary that presents health, environmental, and animal welfare motivations for reducing MAP consumption. Study 1 assessed the documentary's effectiveness at reducing reported MAP consumption after 12 days. This study used methodological innovations to minimize social desirability bias, a widespread limitation of past research. Study 2 investigated discrepancies between the results of Study 1 and those of previous studies by further examining the role of social desirability bias. Study 3 assessed the documentary's effectiveness in a new population anticipated to be more responsive and upon enhancing the intervention content. We found that the documentary did not decrease reported MAP consumption when potential social desirability bias was minimized (Studies 1 and 3). The documentary also did not affect consumption among participants whose demographics suggested they might be more receptive (Study 3). However, the documentary did substantially increase intentions to reduce consumption, consistent with past studies (Studies 2 and 3). Overall, we conclude that some past studies of similar interventions may have overestimated effects due to methodological biases. Novel intervention strategies to reduce MAP consumption may be needed.

Do Health, Environmental and Ethical Concerns Affect Purchasing Behavior? A Meta-Analysis and Narrative Review

Much attention has been given to how we can make consumption more responsible—better for the planet and society. However, research on the associations between consumer purchasing behavior and their psychological concern for health, the environment and ethics lacks consensus on the significance and directionality of these concerns. This study aims to examine how (relatively) important these concerns are in determining consumer purchasing behavior. Systematic searches were conducted in PubMed, EconLit, Web of Science and Scopus databases from 2000 to 2020. Results were summarized through narrative synthesis of the evidence and meta-analysis. The meta-analysis revealed a significant positive correlation between health, environmental and ethical concerns and purchasing behavior, indicating that changes in health, environmental and ethical concerns will result in a consistent shift in purchase behavior towards choices consistent with the concern. This association is susceptible to moderating factors including types of products (food, non-food and non-specific products) and country’s level of economic development. In addition, the health, environmental and ethical concerns appear to have a weaker impact on the actual purchase behavior than on purchase intention, suggesting that interventions should focus on translating these “purchasing intentions” into actual purchasing behaviors. Narrative review of the studies that were not subject to meta-analysis showed good agreement, with almost all relationships reported having the same direction as those indicated by the meta-analysis. Overall, this study suggests that there is substantial potential for marketing strategies aimed at encouraging pro-health, pro-environment and ethical purchasing behaviors.

Psychological Barriers to Pro-Environmental Behaviour Change: A Review of Meat Consumption Behaviours

Meat consumption behaviours contribute significantly to global greenhouse gas emissions. Interventions to enable meat consumption reductions need to consider the psychological barriers preventing behavioural changes. Our aims were twofold; (1) to explore the psychological barriers to reducing meat consumption and how they can be overcome through a Rapid Evidence Review; and (2) to explore the usefulness of integrating the Kollmuss and Agyeman (K&A) model of pro-environmental behaviour and psychological distance, which provides the analytical framework. This review utilised three databases, focussing on empirical studies since 2010, which returned 277 results with seven eligible studies. We found that habit is the most significant psychological barrier to change, however, values and attitudes could act as moderating variables. We found gaps in the behavioural mechanism, indicating the presence of direct and indirect psychological barriers. We identified several actionable policy recommendations, such as utilising co-benefits, the importance of values in messaging, and targeting repeated behaviours. We found that study outcomes did not always translate into policy recommendations, and they were limited by existing policy paradigms. Psychological distance provides additional explanatory power, when combined with the K&A model, therefore, integrating psychological distance across pro-environmental behavioural research and policy could improve the effectiveness of interventions.

Motivated Moral Outrage Among Meat-Eaters

Many meat-eaters experience cognitive dissonance when aware that their eating behaviors contradict their moral values, such as desires to protect the environment or animals from harm. One way in which people morally disengage from their behaviors—and thus avoid dissonance—is to displace responsibility onto others. Aligning with this notion, results of three studies (total N = 1,501) suggest that expressing moral outrage at third-party transgressors reduces dissonance and preserves moral identity among meat-eaters. When participants understood their in-group as responsible for factory farming’s negative impact or read about factory farming’s harms to animals, expressing moral outrage at third-party transgressors reduced guilt and elevated self-rated moral character. Moreover, reflecting on the morally troublesome nature of meat-eating led participants to express more moral outrage at a third-party organization responsible for animal abuse, an effect eliminated by self-affirmation. These findings substantiate moral outrage as a new mechanism to justify meat consumption.

What Influences the Sustainable Food Consumption Behaviours of University Students? A Systematic Review

Objectives: Global environmental challenges demand sustainable behaviours and policies to protect human and planetary health. We aimed to summarize the evidence about the factors related to Sustainable Food Consumption (SFC) behaviours of university students, and to propose an operational categorization of SFC behaviours.

Methods: Seven databases were searched for observational studies evaluating Sustainable Food Consumption (SFC) among university students and that reported at least one behavioural outcome measure. Qualitative synthesis was conducted, and PRISMA guidelines for reporting were followed.

Results: Out of 4,479 unique references identified, 40 studies were selected. All studies examined personal factors, while 11 out of 40 also measured social or situational factors. Except for food waste, females had higher levels of SFC behaviours, but situational factors moderated this association. Knowledge and attitudes showed mixed results. Overall, sustainable food consumers reported healthier lifestyles.

Conclusions: Healthy lifestyle of sustainable food consumers suggests possible synergies between human health and sustainability in terms of motivations for food choice. Moderation effects of social and situational factors on personal factors reveal opportunities to design and examine the effects of choice architecture interventions.

Morally admirable or moralistically deplorable? A theoretical framework for understanding character judgments of vegan advocates

Over the last decade, vegan advocates have become a growing minority. By arguing against animal-product consumption and imposing the virtue-loaded call to "go vegan," advocates have posed a direct challenge to the mainstream dietary ideology (termed "carnism") in hopes of positive social change. As a consequence, while vegan advocates may be admired for their morality and commitment, they may also be derogated with moralistic traits such as arrogance and overcommitment. We call this mixed-valence perception the "vegan paradox" and propose a theoretical framework for understanding it. Next, we develop a future research agenda to test and apply our framework, and inquire vegan advocacy for ethical, health, and environmental aims. Using the perspective of the idealistic vegan advocate as a reference point, we discuss the roles of the advocate's motives for change (i.e., the effectiveness of moral persuasion), the advocate's call for change (i.e., radical versus incremental change), the target's moral and carnist identification, and source attributes of the advocate. Lastly, we qualify our framework by highlighting further conceptual and methodological considerations.

Animals Like Us: Leveraging the Negativity Bias in Anthropomorphism to Reduce Beef Consumption

Our current work contributes to the literature of meat consumption reduction. Capitalizing on the inherent humanizing characteristic of anthropomorphism coupled with leveraging negativity bias, we created a novel approach to reduce meat-eating intention. Using on-pack product stickers, we compare an anthropomorphic message stressing the capacity to experience pain with two other anthropomorphic messages that have been used before in the literature (intelligence and pro-social behavior of animals). We find that an on-pack pain anthropomorphic sticker reduces purchase intentions of the meat product and intention to consume meat in general and is more effective than stickers displaying pro-social or intelligence messages. We also show that the pain message's negative impact on purchase intention is serially mediated by anticipatory guilt and attitude towards meat. In addition, we show that the differential effectiveness of the anthropomorphic messages can be explained by the negativity bias. That is, when the pro-social and intelligence messages were formulated in a negative way (as is pain), all three messages were equally effective at reducing intention to purchase meat and increase intention to reduce meat consumption.

Impact of Plant-Based Meat Alternatives on the Gut Microbiota of Consumers: A Real-World Study

Eating less meat is increasingly seen as a healthier, more ethical option. This is leading to growing numbers of flexitarian consumers looking for plant-based meat alternatives (PBMAs) to replace at least some of the animal meat they consume. Popular PBMA products amongst flexitarians, including plant-based mince, burgers, sausages and meatballs, are often perceived as low-quality, ultra-processed foods. However, we argue that the mere industrial processing of ingredients of plant origin does not make a PBMA product ultra-processed by default. To test our hypothesis, we conducted a randomised controlled trial to assess the changes to the gut microbiota of a group of 20 participants who replaced several meat-containing meals per week with meals cooked with PBMA products and compared these changes to those experienced by a size-matched control. Stool samples were subjected to 16S rRNA sequencing. The resulting raw data was analysed in a compositionality-aware manner, using a range of innovative bioinformatic methods. Noteworthy changes included an increase in butyrate metabolising potential-chiefly in the 4-aminobutyrate/succinate and glutarate pathways-and in the joint abundance of butyrate-producing taxa in the intervention group compared to control. We also observed a decrease in the Tenericutes phylum in the intervention group and an increase in the control group. Based on our findings, we concluded that the occasional replacement of animal meat with PBMA products seen in flexitarian dietary patterns can promote positive changes in the gut microbiome of consumers.

Estimating the effect of moving meat-free products to the meat aisle on sales of meat and meat-free products: A non-randomised controlled intervention study in a large UK supermarket chain

BACKGROUND

Reducing meat consumption could bring health and environmental benefits, but there is little research to date on effective interventions to achieve this. A non-randomised controlled intervention study was used to evaluate whether prominent positioning of meat-free products in the meat aisle was associated with a change in weekly mean sales of meat and meat-free products.

METHODS AND FINDINGS

Weekly sales data were obtained from 108 stores: 20 intervention stores that moved a selection of 26 meat-free products into a newly created meat-free bay within the meat aisle and 88 matched control stores. The primary outcome analysis used a hierarchical negative binomial model to compare changes in weekly sales (units) of meat products sold in intervention versus control stores during the main intervention period (Phase I: February 2019 to April 2019). Interrupted time series analysis was also used to evaluate the effects of the Phase I intervention. Moreover, 8 of the 20 stores enhanced the intervention from August 2019 onwards (Phase II intervention) by adding a second bay of meat-free products into the meat aisle, which was evaluated following the same analytical methods. During the Phase I intervention, sales of meat products (units/store/week) decreased in intervention (approximately -6%) and control stores (-5%) without significant differences (incidence rate ratio [IRR] 1.01 [95% CI 0.95-1.07]. Sales of meat-free products increased significantly more in the intervention (+31%) compared to the control stores (+6%; IRR 1.43 [95% CI 1.30-1.57]), mostly due to increased sales of meat-free burgers, mince, and sausages. Consistent results were observed in interrupted time series analyses where the effect of the Phase II intervention was significant in intervention versus control stores.

CONCLUSIONS

Prominent positioning of meat-free products into the meat aisle in a supermarket was not effective in reducing sales of meat products, but successfully increased sales of meat-free alternatives in the longer term. A preregistered protocol (https://osf.io/qmz3a/) was completed and fully available before data analysis.

Changing Hearts and Plates: The Effect of Animal-Advocacy Pamphlets on Meat Consumption

Social movements have driven large shifts in public attitudes and values, from anti-slavery to marriage equality. A central component of these movements is moral persuasion. We conduct a randomized-controlled trial of pro-vegan animal-welfare pamphlets at a college campus. We observe the effect on meat consumption using an individual-level panel data set of approximately 200,000 meals. Our baseline regression results, spanning two academic years, indicate that the pamphlet had no statistically significant long-term aggregate effects. However, as we disaggregate by gender and time, we find small statistically significant effects within the semester of the intervention: a 2.4 percentage-point reduction in poultry and fish for men and a 1.6 percentage-point reduction in beef for women. The effects disappear after 2 months. We merge food purchase data with survey responses to examine mechanisms. Those participants who (i) self-identified as vegetarian, (ii) reported thinking more about the treatment of animals or (iii) expressed a willingness to make big lifestyle changes reduced meat consumption during the semester of the intervention. Though we find significant effects on some subsamples in the short term, we can reject all but small treatment effects in the aggregate.

Interventions to reduce meat consumption by appealing to animal welfare: Meta-analysis and evidence-based recommendations

Reducing meat consumption may improve human health, curb environmental damage, and limit the large-scale suffering of animals raised in factory farms. Most attention to reducing consumption has focused on restructuring environments where foods are chosen or on making health or environmental appeals. However, psychological theory suggests that interventions appealing to animal welfare concerns might operate on distinct, potent pathways. We conducted a systematic review and meta-analysis evaluating the effectiveness of these interventions. We searched eight academic databases and extensively searched grey literature. We meta-analyzed 100 studies assessing interventions designed to reduce meat consumption or purchase by mentioning or portraying farm animals, that measured behavioral or self-reported outcomes related to meat consumption, purchase, or related intentions, and that had a control condition. The interventions consistently reduced meat consumption, purchase, or related intentions at least in the short term with meaningfully large effects (meta-analytic mean risk ratio [RR] = 1.22; 95% CI: [1.13, 1.33]). We estimated that a large majority of population effect sizes (71%; 95% CI: [59%, 80%]) were stronger than RR = 1.1 and that few were in the unintended direction. Via meta-regression, we identified some specific characteristics of studies and interventions that were associated with effect size. Risk-of-bias assessments identified both methodological strengths and limitations of this literature; however, results did not differ meaningfully in sensitivity analyses retaining only studies at the lowest risk of bias. Evidence of publication bias was not apparent. In conclusion, animal welfare interventions preliminarily appear effective in these typically short-term studies of primarily self-reported outcomes. Future research should use direct behavioral outcomes that minimize the potential for social desirability bias and are measured over long-term follow-up.

The use of Qualitative Comparative Analysis (QCA) to address causality in complex systems: a systematic review of research on public health interventions

Background

Qualitative Comparative Analysis (QCA) is a method for identifying the configurations of conditions that lead to specific outcomes. Given its potential for providing evidence of causality in complex systems, QCA is increasingly used in evaluative research to examine the uptake or impacts of public health interventions. We map this emerging field, assessing the strengths and weaknesses of QCA approaches identified in published studies, and identify implications for future research and reporting.

Methods

PubMed, Scopus and Web of Science were systematically searched for peer-reviewed studies published in English up to December 2019 that had used QCA methods to identify the conditions associated with the uptake and/or effectiveness of interventions for public health. Data relating to the interventions studied (settings/level of intervention/populations), methods (type of QCA, case level, source of data, other methods used) and reported strengths and weaknesses of QCA were extracted and synthesised narratively.

Results

The search identified 1384 papers, of which 27 (describing 26 studies) met the inclusion criteria. Interventions evaluated ranged across: nutrition/obesity (n = 8); physical activity (n = 4); health inequalities (n = 3); mental health (n = 2); community engagement (n = 3); chronic condition management (n = 3); vaccine adoption or implementation (n = 2); programme implementation (n = 3); breastfeeding (n = 2), and general population health (n = 1). The majority of studies (n = 24) were of interventions solely or predominantly in high income countries. Key strengths reported were that QCA provides a method for addressing causal complexity; and that it provides a systematic approach for understanding the mechanisms at work in implementation across contexts. Weaknesses reported related to data availability limitations, especially on ineffective interventions. The majority of papers demonstrated good knowledge of cases, and justification of case selection, but other criteria of methodological quality were less comprehensively met.

Conclusion

QCA is a promising approach for addressing the role of context in complex interventions, and for identifying causal configurations of conditions that predict implementation and/or outcomes when there is sufficiently detailed understanding of a series of comparable cases. As the use of QCA in evaluative health research increases, there may be a need to develop advice for public health researchers and journals on minimum criteria for quality and reporting.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-10926-2.

Prescribing vegetarian or flexitarian diets leads to sustained reduction in meat intake

Many people agree that reducing the consumption of meat has good ends (e.g., for animal welfare, the environment, and human health). However, the question of which advocacy strategies are most effective in enabling wide-spread meat reduction remains open. We explored this by prescribing four different meat reduction diets to omnivorous participants for a seven-day adherence period, and studied their meat consumption over time. The diets included a Vegetarian diet, and three flexitarian diets (Climatarian - limit beef and lamb consumption; One Step for Animals - eliminate chicken consumption; Reducetarian - reduce all meat consumption). Results showed pronounced differences between groups in meat consumption during the adherence period, where the Vegetarian group ate significantly less meat than the flexitarian groups. All groups decreased their meat intake in the weeks following the adherence period compared to baseline, however, there were no significant group differences in the level of decrease over time. Participants also changed their attitudes toward meat and animals from pre-to post-intervention, and decreases in commitment toward and rationalization of meat-eating partially mediated change in meat intake. These findings reveal that the diet assignments had some impact on participants' meat consumption and attitudes even after the prescribed adherence period had ended. However, the sustained decrease in consumption did not vary depending on what meat reduction strategy was originally used.

Two Birds, One Stone: The Effectiveness of Health and Environmental Messages to Reduce Meat Consumption and Encourage Pro-environmental Behavioral Spillover

There is a growing consensus that reducing excess meat consumption will be necessary to meet climate change targets, whilst also benefitting people’s health. Strategies aimed at encouraging reduced meat consumption also have the potential to promote additional pro-environmental behaviors through behavioral spillover, which can be catalyzed through an increased pro-environmental identity. Based on this, the current study tested the effectiveness of a randomized two-week messaging intervention on reducing red and processed meat consumption and encouraging pro-environmental behavioral spillover. Participants were undergraduate students in the United Kingdom (n = 320 at baseline) randomly allocated to four conditions in which they received information about the health, environmental, or combined (health and environmental) impacts of meat consumption, and a no-message control. The results showed that receiving information on the health and/or environmental impacts of meat was effective in reducing red and processed meat consumption compared to the control group during the intervention period, with some effects remaining one-month later. However, the intervention did not have any effect on pro-environmental identity and there was little evidence of behavioral spillover. Implications for future research and interventions aimed at reducing meat consumption are discussed.

Changing diets and the transformation of the global food system

An aspirational global food system is one that delivers across a suite of the Sustainable Development Goals (SDGs), including universal access to healthy diets, which can also codeliver on climate and environment SDGs. The literature has downplayed the relative contribution of dietary change to sustainable food systems. In this perspective article, we argue that the potential for positive transformational change in diets should not be underestimated, for two sets of reasons. First, the dynamism of diets over long-term and, especially, recent history shows the potential for rapid and widespread change, including toward more diverse and healthier diets. Second, contemporary behavioral research demonstrates promising tactics to influence consumers' dietary choices. Since the entire food system creates the circumstances of those choices, the most effective strategies to shift diets will involve multiple approaches that deliberately aim not just to influence consumers themselves but also to incentivize all actors in the food systems, taking into account multiple agendas and values. The effectiveness of actions will depend on the political economy at local, national, and global levels. Overall, there are reasons to be hopeful about the potential for accelerated global dietary change, given both historic trends and the growing suite of tools and approaches available.

A scoping review of policies promoting and supporting sustainable food systems in the university setting

BACKGROUND

Transitioning towards sustainable food systems for the health of the population and planet will require governments and institutions to develop effective governance to support the adoption of sustainable food practices. The aim of the paper is to describe current governance within Australian and New Zealand universities designed to support sustainable food systems.

METHODS

A systematic search of governance documents to support sustainable food systems within Australian and New Zealand universities was conducted. Data were obtained from 1) targeted websites 2) internet search engines and 3) expert consultations. Inclusion criteria consisted of university governance documents including by-laws, policies, guidelines, frameworks, and procedures that support sustainable food systems.

RESULTS

Twenty-nine governance documents across nineteen Australian and New Zealand universities were included for synthesis, including waste management policies (n = 3), fair-trade/procurement policies (n = 6), catering and or event guidelines (n = 7) and catering policies (n = 2), and environmental management plans (n = 11). The main strategies adopted by universities were sustainable waste management and prevention (e.g. reducing landfill, reducing wasted food, (27%)), ethical procurement practices (i.e. fair-trade (27%)) and environmentally sustainable food consumption (e.g. local, seasonal, organic, vegetarian food supply (14.5%)). Only 12.5% of universities addressed all three of the main strategies identified.

CONCLUSIONS

This study indicates that while sustainable food systems are considered in some university governance documents, efforts are predominantly focused on aspects such as waste management or procurement of fair-trade items which as stand-alone practices are likely to have minimal impact. This review highlights the scope of universities to provide strong leadership in promoting and supporting sustainable food systems through holistic institutional policies and governance mechanisms.

Animal Agriculture and Climate Change in the US and UK Elite Media: Volume, Responsibilities, Causes and Solutions

Animal agriculture is a major producer of greenhouse gas emissions, equivalent to 14.5% of global emissions, which is approximately the same size as the transportation sector. Global meat consumption is projected to grow, which will increase animal agriculture's negative impact on the environment. Public awareness of the link between animal food consumption and climate change is low; this may be one of many obstacles to more effective interventions to reduce meat consumption in Western diets, which has been proposed by many research institutions. This study analyzes how much attention the UK and US elite media paid to animal agriculture's role in climate change, and the roles and responsibilities of various parties in addressing the problem, from 2006 to 2018. The results of the quantitative media content analysis show that during that period, volume of coverage remained low, and that when the issue was covered, consumer responsibility was mentioned more than that of governments or largescale livestock farms. In similar fashion, a range of options around personal dietary change was far more prominent in the media discussion of solutions than government policies, reforming agricultural practices or holding major animal food companies accountable for their emissions.

Using consumption and reward simulations to increase the appeal of plant-based foods

The production of meat is a main contributor to current dangerous levels of greenhouse gas emissions. However, the shift to more plant-based diets is hampered by consumers finding meat-based foods more attractive than plant-based foods. How can plant-based foods best be described to increase their appeal to consumers? Based on the grounded cognition theory of desire, we suggest that descriptions that trigger simulations, or re-experiences, of eating and enjoying a food will increase the attractiveness of a food, compared to descriptions emphasizing ingredients. In Study 1, we first examined the descriptions of ready meals available in four large UK supermarkets (N = 240). We found that the labels of meat-based foods contained more references to eating simulations than vegetarian foods, and slightly more than plant-based foods, and that this varied between supermarkets. In Studies 2 and 3 (N = 170, N = 166, pre-registered), we manipulated the labels of plant-based and meat-based foods to either include eating simulation words or not. We assessed the degree to which participants reported that the description made them think about eating the food (i.e., induced eating simulations), and how attractive they found the food. In Study 2, where either sensory or eating context words were added, we found no differences with control labels. In Study 3, however, where simulation-based labels included sensory, context, and hedonic words, we found that simulation-based descriptions increased eating simulations and attractiveness. Moreover, frequent meat eaters found plant-based foods less attractive, but this was attenuated when plant-based foods were described with simulation-inducing words. We suggest that language that describes rewarding eating experiences can be used to facilitate the shift toward healthy and sustainable diets.

Increasing the Proportion of Plant-Based Foods Available to Shift Social Consumption Norms and Food Choice among Non-Vegetarians

Increasing the relative availability of plant-based (versus animal source) foods seems promising in shifting consumption, but it remains unknown how and under what circumstances this happens. We performed two availability manipulations including different foods. The impact on food choice, social norm perceptions about what others do (descriptive) or approve of (injunctive), and salience was assessed. Non-vegetarian participants were visually (Study 1, n = 184) or physically (Study 2, n = 276) exposed to (a) four plant-based and two animal source foods or (b) vice versa. Participants chose one food item, either hypothetically (Study 1) or actually (Study 2), and reported the perceived social norms and salience of plant-based and animal source foods. The results showed no direct effects on food choice, injunctive norms, or salience. An increased proportion of plant-based (versus animal source) foods was interpreted in Study 1 as plant-based foods being less often chosen by others, whereas in Study 2, these foods were interpreted as being more often chosen (marginally significant), while animal source foods were interpreted as being less often chosen. The results suggest that a higher availability of plant-based foods influences descriptive norms, but future research should examine aspects potentially contributing to the contradictory normative interpretations (e.g., norm salience).