Most people are reluctant to reduce meat and dairy intake

In line with such norms, most people are hesitant to reduce their meat and dairy intake. Barriers such as perceiving meat consumption as commonplace, being unfamiliar with plant-based foods, and lacking skills and knowledge to prepare them in tasty and nutritionally adequate ways have been identified as hindering Swedish consumers in reducing their meat intake^{(Reference Collier, Oberrauter and Normann27)}. Similarly, participants in a recent UK-based qualitative survey pointed to perceptions of low availability, affordability and health benefits of plant-based foods as important barriers when trying to reduce meat and dairy intake^{(Reference Wehbe, Banas and Papies28)}. Habits, and the self-control needed for behaviour change, further challenge the transition away from meat-heavy diets, which is also impeded by cultural norms about meat eating and media discourse that cater to meat eating as the acceptable status quo^{(Reference Wehbe, Banas and Papies28–Reference Macdiarmid, Douglas and Campbell30)}. Synthesising research on the barriers and enablers for transitioning to a plant-based diet, Graça et al.^{(Reference Graça, Godinho and Truninger31)} identified skills and information, enjoyment motives and social norms and prejudice as key barriers, whereas positive taste expectancies and positive views of plant-based lifestyles were seen as enablers.

To address these barriers, significant ‘upstream’ and ‘midstream’ interventions in the food system are required^{(Reference Hampton and Whitmarsh32)}. This includes, for example, incentivising the production of plant-based over animal-based foods, updating dietary guidelines and making plant-based foods the default in public settings. Such concerted changes would increase exposure towards plant-based foods, shift social norms in favour of consuming plant-based foods, and hence support attitude and habit change. We discuss such food system interventions in more detail at the end of this review. An important complementary strategy to increase the acceptability and likely success of such measures, however, is to increase taste expectations of plant-based foods among mainstream consumers. Indeed, taste expectations and enjoyment in particular are a key obstacle to shifting towards more sustainable diets. Although vegetarian and vegan foods are expected to be healthier and more environmentally friendly, most omnivores expect these foods to be less enjoyable to eat compared to meat-based foods (e.g.^{(Reference Bryant33–Reference Vural, Ferriday and Rogers36)}). Similarly, meat and dairy reducers reported that liking animal-based foods, and finding plant-based foods less appealing hindered their dietary change^{(Reference Wehbe, Banas and Papies28)}. Indeed, they indicated to be willing to try more plant-based foods if they tasted better. In order to examine the psychological processes underlying these taste expectations and related motivational processes in the consumption of meat- and plant-based foods, we recently examined how people cognitively represent these foods.

A grounded cognition approach to understanding food motivation

Cognitive representations may be important as they can motivate and shape behaviour, often outside of conscious awareness. When examining the cognitive representations of meat- and plant-based foods, we adopted the theoretical framework of the grounded cognition theory of desire and motivated behaviour^{(Reference Papies, Barsalou and Rusz37–Reference Papies, Barsalou, Hofmann and Nordgren39)}, which proposes that during each eating or drinking episode, people store rich representations of the experience in memory. These representations can include, for example, information about the smell, taste and the texture of the food, information about the motor actions of eating it, information about the physical location, time, occasion and other people present, as well as internal states such as bodily feelings, emotions, thoughts and experiences of (dis)pleasure or enjoyment.

When one later encounters a part of such a cognitive representation one has formed of eating a food (e.g. the place where one has eaten a specific food; seeing the food), this can activate remaining features of the representation, which can then be simulated, or re-experienced, in response to this cue. As an example, if one frequently eats a burger on a Friday night in the local gastro pub, later entering the pub, or hearing mention of a burger, may trigger a re-experience of what it is like to eat the burger, including picking it up, what it feels and tastes like, who else is around, the sounds of the pub and what the experience feels like. Indeed, neuro-imaging research has shown that simply viewing food pictures in an functional MRI scanner activates those areas of the brain that are also involved when actually eating, including primary taste areas, motor areas and reward areas (see^{(Reference Chen, Papies and Barsalou40)}, for a review). This suggests that people simulate, or re-experience, eating the food when they see a picture of it. Critically, the degree that these simulations include reward experiences, such as liking the taste of the food, or feeling good from eating it, can create desire, and can lead to motivated behaviour, such as choosing a food, preparing it or leaving the house to purchase it.

In line with this theory, research on the cognitive representations of foods and drinks has confirmed that people hold rich, multifaceted representations of these stimuli that seem to be shaped by their consumption experiences. When participants were asked to ‘simply describe’ a variety of beverages, such as Coca-Cola and water^{(Reference Papies, Claassen and Rusz41)}, they listed hundreds of unique features for each drink, pointing to highly idiosyncratic consumption experiences informing their cognitive representations (e.g. ‘sweet’, ‘sticky’, ‘tangy’, ‘on a hot day’, ‘at the gym’, ‘satisfying’, ‘nice’, ‘awake’, ‘guilt’, ‘energy’). Related research on alcoholic drinks showed that features referring to the social drinking context were especially salient for alcoholic drinks that participants consumed frequently^{(Reference Keesman, Aarts and Ostafin42)}. Similarly, when asked to describe twenty different dishes either without further instructions, or with instructions to focus specifically on sensory features, eating context or hedonic experiences, participants listed between 1237 and 1479 unique features per dish. These frequencies suggest large variability in individual representations that likely results from a wide array of individual eating experiences with a food^{(Reference Farrar and Papies43)}.

Preferred foods are cognitively represented through rewarding eating experiences

Across experiments and domains, we have found that foods and drinks that are rated as more appealing by participants are represented more in terms of what it is like to consume them than foods and drinks seen as less appealing. Specifically, the proportion of consumption and reward features, which reflect sensory, context or reward aspects of the consumption experience, is typically higher for more appealing foods and drinks e.g. for sugar-sweetened beverages compared to water, and for unhealthy snacks compared to fresh vegetables^{(Reference Papies, Claassen and Rusz41,Reference Papies44)} . Less appealing foods and drinks are more represented in terms of what they look like, in terms of food and drink categories, or with reference to ingredients or health implications. In other words, people think about foods and drinks that they enjoy consuming in terms of what they taste and feel like, and in terms of the situations where they would eat or drink them, more than for less preferred foods and drinks.

Critically, findings across experiments and domains also show that representing a food or drink in terms of consumption and reward experiences predicts appeal ratings, desire to consume, as well as consumption intentions and behaviour^{(Reference Papies, Claassen and Rusz41–Reference Papies44)}. In a recent large experiment^{(Reference Farrar and Papies43)}, we asked 720 participants to describe twenty foods, indicate their intentions to eat them over the next 30 days, and then contacted them again to assess their actual consumption 30 days later. We found that describing a food more in terms of rewarding eating experiences (i.e. with consumption and reward features) predicted intentions to consume, which in turn predicted actual intake over the follow-up period. In sum, cognitively representing a food in terms of consumption and reward experiences reflects the motivation to eat it.

Cognitive representations of meat-based and plant-based foods

Similar to the findings described earlier, we recently studied the representations that people hold of meat- and plant-based foods, to understand whether they could provide insights into the reluctance of mainstream consumers to switch to more plant-based diets^{(Reference Davis, Harkins and Papies45)}. In two large-scale experiments (N 220 and N 843), we asked omnivores and vegans to describe a number of meat- and plant-based foods (e.g. beef burger, falafel burger; pork ramen, tofu ramen). The listed features were then coded as consumption and reward features (i.e., referring to sensory aspects, eating context, or immediate positive effects of consuming the food), or as situation-independent features (i.e. referring to visual aspects, categories, health implications, ingredients, etc.). Across the two experiments, we also assessed food attractiveness, how often participants typically consumed each food, likelihood of ordering each food in a restaurant, intentions to consume it and actual intake over a 30-d period.

Again, we found high numbers of unique features for all twenty dishes (Experiment 1 = 3910; Experiment 2 = 7346), pointing to the large variability in how people cognitively represent the foods. Analysing the categories of the features listed showed that omnivores described meat-based foods more with consumption and reward features than plant-based foods, using words such as tasty, spicy, delicious, filling, meaty, hot and juicy. Notably, we found exactly the opposite pattern for vegans: they described plant-based foods more with consumption and reward features than meat-based foods, using words such as tasty, spicy and filling. In other words, each group described foods that are compatible with their diet and thus frequently consumed more in terms of rewarding eating experiences than foods that are incompatible with their diet or infrequently consumed. Indeed, higher typical consumption frequency was associated with describing a food more in terms of consumption and reward features, which is consistent with related studies on foods and drinks^{(Reference Papies, Claassen and Rusz41,Reference Farrar and Papies43)} .

These findings suggest that omnivores simulate rewarding eating experiences when thinking about meat-based foods, but not when thinking about plant-based foods. In contrast, vegans simulate rewarding eating experiences when thinking about plant-based foods, but not meat-based foods. When thinking about plant-based foods, omnivores were more likely to list features related to health (e.g. healthy), ingredients (e.g. chickpeas) or categories (e.g. vegetarian, vegan), whereas vegans were more likely to list features about meat-based foods related to the social political context of consuming meat (e.g. cruel, carcass, bad for the environment). While these features are often accurate, they do not reflect or create desire for a food, and do not motivate consumption in the moment.

Furthermore, as we had hypothesised, representing a dish in terms of rewarding eating experiences was systematically associated with eating motivation. Specifically, we found that consumption and reward features predicted how attractive participants rated a dish, how likely they would be to order it in a restaurant, their intentions to eat it, and their actual consumption over 30 days. However, this association with actual consumption disappeared when controlling for typical consumption, suggesting that consumption habits are strongly aligned with behaviour, and both are reflected in consumption and reward descriptions. In other words, past consumption frequency, or habitual consumption, was a strong predictor of consumption, and participants represented these habitual foods in terms of eating and enjoying them.

Overall, these findings show that people are more likely to simulate eating and enjoying food that is compatible with their dietary pattern and that they consume frequently, and that these simulations motivate future consumption. This could provide insights into why omnivores are hesitant to shift towards plant-based foods: they do not represent them in rewarding ways that motivate consumption.

Plant-based foods are presented to others in less appealing ways

In line with these findings, we found that plant-based foods are also described to others in less appealing ways than meat-based foods, for example on food packages^{(Reference Papies, Johannes and Daneva46)}. In an observational UK study examining the labels of 240 meat-based, vegetarian and plant-based ready-meals available in four supermarkets, we coded the language used in the food descriptions according to the same categories as in the experiments described earlier (i.e. as consumption and reward features or other features). Here, we found that meat-based foods tended to be labelled with a higher proportion of consumption-related words than vegetarian and plant-based foods, which in turn had a higher proportion of more abstract, distal features (e.g. ingredients, health implications, food categories). This suggests that in a retail context, plant-based foods may be presented in a disadvantageous way, with fewer references to the rewarding consumption experiences that motivate desire for food, and that could entice omnivores to try out plant-based foods (see also^{(Reference Turnwald, Jurafsky and Conner47)}).

We found the same pattern of language in food posts on the social media platform Instagram^{(Reference Davis and Papies48)}. In two observational studies, we coded the words used as hashtags for posts (N 852 and N 3104) about meat- or plant-based foods. As we had predicted, and analogous to the language about supermarket ready-meals, posts about meat-based foods contained more consumption and reward features than posts about plant-based foods, which instead contained more words related to ingredients, health and food categories. This suggests that even those who post about plant-based foods on this social media platform do this in a way that may not create motivation to eat them.

Notably, posts about plant-based foods contained a high proportion of words reflecting vegan identity (#veganfood, #whatveganseat, #govegan, #veganlife) as well as words that may help other users identify useful dishes or recipes (#healthy, #recipes, #breakfast, #dinner). This may reflect vegans' motivation to create a positive social identity and provide support to other vegans, rather than a motivation to make specific foods appealing in a way that signals immediate reward from an enjoyable consumption experience. While this may be an important function of social media communication about plant-based foods, it is not likely to create desire for these foods among mainstream consumers, i.e. omnivores.

In a separate experiment where we asked participants to compose hypothetical Instagram posts^{(Reference Davis, Silberhorn and Papies49)}, we found that both omnivore and vegan participants used more consumption and reward features when promoting meat-based foods compared to plant-based foods. Participants used more situation-independent features for plant-based dishes, especially when appealing to a vegan audience, and especially using words related to the sociopolitical context of vegan food and to identity (e.g. #crueltyfree, #whatveganseat). This demonstrates that meat foods are typically promoted in terms of their consumption and reward features, and plant-based foods in terms of health, identity or sociopolitical features, even by vegans. Although our previous research suggests vegans spontaneously think about plant-based foods in rewarding ways^{(Reference Davis, Harkins and Papies50)}, these findings suggest that they present these foods in less rewarding ways in public discourse on social media, even when the goal is to create appeal among omnivore audiences. Furthermore, these findings may reflect the assumption that omnivores are hedonically motivated (and hence appealed to with rewarding eating experiences), and vegans are politically motivated (and hence appealed to with sociopolitical and identity language). This may drive omnivore–vegan polarisation, and hence further hinder the mainstream transition to sustainable diets.

Creating desire for plant-based foods through eating simulation language

How can the appeal of plant-based foods be increased for mainstream consumers? As we have reviewed earlier, thinking about a food or drink in terms of rewarding consumption experiences, or simulating consuming and enjoying it, has been found to predict desire and intake (e.g., ^{(Reference Papies, Claassen and Rusz41,Reference Farrar and Papies43,Reference Davis, Harkins and Papies50)} ). Similarly, experimental research on inducing consumption simulations has shown that simulations increase salivation, which can be seen as an indirect measure of desire to consume a food^{(Reference Keesman, Aarts and Vermeent51)}. What are the implications of this research for increasing the appeal of plant-based foods?

In an experiment among UK omnivores, we manipulated the descriptions of twenty plant-based and twenty meat-based ready-meals available in UK supermarkets. Specifically, we created descriptions that either contained only words referring to food categories (e.g. ‘stir-fry’, ‘burger patty’), ingredients (e.g. ‘mushroom’, ‘vegetables’) and composition of the food (e.g. ‘added’, ‘assorted’), or that reflect rewarding consumption simulations by referring to sensory (e.g. ‘aromatic’, ‘creamy’), context (e.g. ‘Sunday lunch’, ‘Pub-favorite’) and hedonic (e.g. ‘indulgent’, ‘tasty’) aspects of the consumption experience. Findings showed that simulation-focused labels increased the perceived attractiveness of both meat- and plant-based foods, and they increased the degree to which participants reported the descriptions made them think about what it would be like to eat the food. In other words, the simulation labels triggered spontaneous consumption simulations. This increase in simulations mediated the effect on attractiveness. Notably, the effect of simulation-focused labels on the attractiveness of plant-based foods was especially pronounced among more frequent meat-eaters. Overall, this work suggests that presenting plant-based foods in ways that evoke rewarding simulations of eating them can increase their appeal.

These findings are consistent with a number of large-scale field experiments on changing the labels of vegetable foods in food service settings. For example, Turnwald and Crum^{(Reference Turnwald and Crum52)} found that, across four field studies, taste-focused labelling (e.g. ‘Crispy veggie straws with decadent miso dip’) increased and sustained plant-based and vegetarian food sales over a 2-month period, and also improved post-consumption ratings of vegetable deliciousness, in comparison to health-focused labelling (e.g. ‘Fibre-packed vegetables with nutritious miso sauce’). In related research, taste-focused labels (e.g. ‘Herb n’ honey balsamic glazed turnips') increased vegetable selection by 29 % compared with health-focused labels (e.g. ‘Healthy choice turnips’), and by 14 % compared with basic labels (e.g. ‘Turnips’); this was mediated by increased expectation of positive taste experiences^{(Reference Turnwald, Bertoldo and Perry53)}. Similarly, Gavrieli et al.^{(Reference Gavrieli, Attwood and Wise54)} found that appealing names for plant-rich dishes (e.g. ‘Sweet velvety soup with collard greens’) increased the amount of food taken per plate by 43⋅9 % compared to basic labels (‘Collard Greens Vegetable Soup’). Bacon et al.^{(Reference Bacon, Wise and Attwood55)} showed that attractive descriptions (e.g. ‘Cumberland Spiced Veggie Sausages and Mash’) of plant-rich dishes increased sales by up to 76 %, in comparison to their basic descriptions (‘Vegetarian Sausages and Mash’). Furthermore, research by Garaus et al.^{(Reference Garaus, Weismayer and Steiner56)} suggests that texture descriptions may be especially effective at increasing food appeal in the field. Together, this research demonstrates the real-world impact of dish labelling focused on eating experiences, which allows people to simulate the sensory and reward aspects of eating a plant-based food.

Avoiding vegan labels

Where labels focusing on eating experiences may be helpful to promote the appeal of plant-based foods, labels referring to veganism should be avoided, as they may reduce the appeal of plant-based foods. Despite the climate emergency, veganism is still a dietary pattern that deviates from mainstream diets and challenges traditional norms, beliefs and values about consuming meat and dairy, often for moral or ethical reasons. People who consume meat can feel threatened by vegans' moral stance^{(Reference O'Connor and Monin57)} and experience cognitive dissonance^{(Reference Rothgerber58)}. Being exposed to vegans can also activate so-called ‘do-gooder’ derogation, a psychological phenomenon that refers to the tendency to evaluate individuals who engaged in moral behaviours negatively^{(Reference Minson and Monin59)}. In addition, vegans are heavily and negatively stereotyped^{(Reference De Groeve, Rosenfeld and Bleys60,Reference Wehbe, Duncan and Banas61)} , and omnivores have been found to rate the label ‘plant-based’ more positively than the label ‘vegan’^{(Reference Papies, Johannes and Daneva46)}. In sum, words related to veganism, such as ‘vegan’ as a label for plant-based foods, are likely to activate a host of negative associations in most mainstream consumers, which may negatively affect the appeal of plant-based foods^{(Reference Krpan and Houtsma62)}. Hence, these should be avoided when labelling plant-based foods to create appeal for mainstream consumers.

The special role of eating context

It may be worth pointing to the special role that eating context may have in creating desire for food. According to the grounded cognition theory of desire and motivated behaviour, context cues form part of the representations of foods and drinks that people form during consumption experiences^{(Reference Papies, Barsalou and Rusz37–Reference Papies, Barsalou, Hofmann and Nordgren39)}. As a result, cueing a context where a rewarding food has previously been consumed may increase desire for that food, as it triggers simulations of eating it. Indeed, supporting that reasoning, experiments in which participants were presented with foods in a congruent or an incongruent eating context (e.g. popcorn in the cinema v. popcorn in the kitchen) showed that the congruent context increased desire for the presented food, mediated by eating simulations^{(Reference Papies, van Stekelenburg and Smeets63)}. Social aspects of the eating context may be particularly important, as cueing foods with ‘eating together’ compared to ‘eating alone’ has been shown to increase the activation in reward areas in the brain in neuro-imaging research^{(Reference Huang, Wang and Wan64)}.

Building on this work, we recently instructed participants to list three to five words that relate to either the typical, sensory, context, hedonic or health aspects of twenty savoury dishes, before measuring present moment desire to consume each dish^{(Reference Farrar and Papies43)}. We found that participants focusing on the sensory, context or hedonic aspects of a food described the foods more in terms of overall consumption and reward experiences (i.e. sensory, context and hedonic words combined) than participants listing either the typical or health words, which in turn was associated with increased desire for the foods. The effects of the ‘context-focus’ manipulation were particularly pronounced. This suggests that focusing on the context aspect of the consumption experience, such as where, with whom and under which circumstances one would eat a food (e.g. at the pub, with friends, weekend, family dinner) triggers a mental simulation of all the aspects that are present during the experience (i.e. sensory, context and hedonic parts of the experience), which underlies food desire. Overall, these findings suggest that context cues may be an effective (and likely under-used) way of eliciting rich and vivid imagery of rewarding eating situations to create desire for a food. As little previous work has focused on this role of context cues, future research may be needed to address this in more detail. In the meantime, we encourage readers to consider the role of rewarding eating contexts when communicating about food to create desire.

Food system interventions to support sustainable diets

In addition to improving the ways that plant-based foods are described, other interventions are urgently needed in the food system to support the mainstream transition to more sustainable diets. Addressing the way plant-based foods are offered and presented, for example, research has shown that doubling the number of vegetarian options on a menu from 25 to 50 % can increase sales by 41–79 %^{(Reference Garnett, Balmford and Sandbrook65)}. Furthermore, in a recent meta-analysis of university cafeteria setting research^{(Reference Chang, Wooden and Rosman66)}, presenting the vegetarian option first and widely distanced from the meat option^{(Reference Garnett, Marteau and Sandbrook67)} was the most effective meat reduction intervention out of thirty-one studies. Other changes to the choice architecture or use of ‘nudging’ techniques, such as changing the default menu choice to plant-based^{(Reference de Vaan, van Steen and Müller68)}, can also help reduce meat-based food choices via contextual and environmental modifications (see^{(Reference Graça, Campos and Guedes69)} for a scoping review). Indeed, these out-of-home meal contexts can shape the habits of a large group of consumers from varied demographic backgrounds, without having to rely on effortful strategies such as nutrition or sustainability education^{(Reference Pfeiffer, Speck and Strassner70)}.

Interventions in school food systems are especially promising for reducing the demand for meat and dairy foods^{(Reference Roque, Graça and Truninger71)}. As children consume on average 30 % of their daily food intake in school^{(Reference Nathan, Janssen and Sutherland72)}, school food is an important area to shape children's eating behaviours and preferences, which will shape their eating behaviour as adults through the development of eating habits. In addition, increasing the consumption of plant-based foods in school may facilitate similar transitions in the home environment. Animal-based dishes contribute greatly to school food's GHG emissions and water usage, with meat dishes responsible for over half of carbon emissions in English primary schools^{(Reference De Laurentiis, Hunt and Rogers73)}. A recent scoping review into sustainable school food interventions found that more environmentally sustainable menus, including those that were meat-free, vegetarian and followed a Nordic diet, had lower GHG emissions and water footprint than previous menus^{(Reference Gardner, Burton and Sinclair74)}. There were some instances of increased food waste; however, these interventions and accompanying qualitative research seem promising for children's acceptance and liking of more plant-based school food. Gardner et al.^{(Reference Gardner, Burton and Sinclair74)} conclude that further school food interventions aiming to improve both health and the environmental sustainability, including changing menus to be more plant-based, can contribute towards shaping children's norms about eating behaviours. Future research might also assess the effectiveness of consumption and reward labelling of plant-based dishes in this context, and examine whether this strategy works to increase the taste expectancies of plant-based foods among children as well. It is possible that this strategy can increase acceptance of plant-based school meals among children and parents, and reduce food waste in schools.

More generally, significant transformations are needed across food systems to increase equitable access to healthy, sustainable and affordable food, to address both malnourishment and overconsumption, and to reduce the environmental impact of food systems. This includes measures such as updating dietary guidelines to support a shift towards more plant-based diets; increasing health and sustainability standards for public food procurement; large reductions in food waste; supporting and incentivising organisations to shift away from producing, procuring and offering foods heavy in animal products; and significant changes in farming practices and re-organising land use to prioritise healthy and sustainable food production and nature restoration over industrial production of animal foods^{(Reference Willett, Rockström and Loken3,Reference Dimbleby75,76)} . In this critical transition, organisations and individual decision makers within organisations (e.g. universities, health-care providers, food service providers) have significant power to catalyse and facilitate these transformative shifts, through acting as transformative investors, role models and courageous decision makers who prioritise planetary health over the destructive behaviours associated with the status quo^{(Reference Papies, Barsalou, Claassen and Gawronski38,Reference Garnett and Balmford77–Reference Papies, Nielsen and Soares79)} .