Regarding the PLS model’s results, it is particularly interesting to discuss the explanation of variance. PI could be explained to a satisfactory extent (R2 = 0.726), which fits the research model’s theoretical underpinning in the form of TRA. ATT was identified as a necessary and sufficient condition for PI, which provides evidence from a novel methodological perspective that TRA’s mechanisms offer a valid framework to explain behavioral intentions. Further, the strength of the relation (path coefficient = 0.816) indicates a quasi-symmetric link (Woodside 2013); i.e., while high values of ATT evoke high values of PI, low values of ATT lead to the opposite. In the sustainability field, symmetric relations are not the norm, and, as such, this finding is fairly surprising.
DIET and ATT could be explained to a moderate extent (R2 values of 0.456 and 0.478, respectively). In both cases, we used the same predictors and achieved very similar results; however, we also included a link between DIET and ATT. This additional influence on ATT leads to the slightly increased R2 in comparison to DIET (without the link, the value decreases to 0.458). Consequently, although the order of independent variables differs in terms of their effect sizes, both ATT and DIET are affected similarly in total. In both cases, HCON yields only a negligible impact. The role of ECON is ambiguous in our data: for DIET, its impact is far below being considered a small effect (f2 = 0.008), and for ATT, although still falling short of the threshold, the miss is reasonably close (f2 = 0.017). However, based on interpretation guidelines for effect size, we may conclude that in both cases, ECON does not have a substantial influence. Concerning the remaining two predictors, PCE exhibits the largest effect on ATT but only a small impact on DIET. AWEL does not appear to play a role for ATT; however, it is the most substantial predictor for DIET with a large effect (f2 = 0.423). Altogether, ECON and HCON behave similarly as predictors for ATT and DIET, and PCE and AWEL switch their roles. We explain this alteration as a result of consumers’ different perceptions regarding DIET and ATT: individuals that are worried about animal welfare may exert a direct, immediate impact by avoiding meat-based products in their nutrition; however, in the case of ATT, this influence is more indirect in nature, as buying substitutes naturally does not exclude purchasing meat but may be a complement. The link between DIET and ATT provides further evidence, indicating that after having selected nutrition to follow, consumers that decrease or abandon meat intake are willing to try out novel, plant-based products in addition to their current food choice. For ATT, on the other hand, an individual’s belief of being able to make a change (i.e., PCE) yields the most substantial influence, which appears reasonable as plant-based food substitutes are not restricted to replacing meat, and instead may also compensate for other products such as honey, milk, and eggs. That is, consumers that are not worried about animal welfare may nevertheless note negative environmental impacts exerted through current practices of large-scale production and seek alternatives.
Consumers’ ATT may also be affected by negative framings of meat-based nutrition, such as reports of factory farming and multi-resistant germs, and define plant-based diets as a reasonable alternative. Consequently, adverse beliefs about a meat-based diet, e.g., food safety concerns (Michaelidou and Hassan 2008), could predict ATT as well.
A surprising result is the absence of an effect of AWEL on ATT. It appears reasonable to assume the influence of consumers’ concerns for animal welfare on their attitude towards plant-based food substitutes; however, our empirical data did not reveal such a relation. This finding might be explained by the vast amount of vegetarian and vegan groceries that render it optional to consume food substitutes. Consequently, DIET plays only a minor role in shaping individuals’ ATT (f2 = 0.038). Still, DIET is not a necessary condition for ATT, indicating that plant-based food substitutes are of interest to consumers regardless of their diet. Similarly, concerns for one’s health (i.e., HCON) were not found to play any role in intention formation, and, more striking, they do not appear to impact consumers’ dietary behavior.
ECON, which captures individuals’ environmental concerns, is altruistic in nature and, thus, conceptually close to AWEL. Nevertheless, its impact on ATT is weak, and the influence on DIET is far off being considered even a small effect (f2 = 0.008). This result seems counterintuitive, as factory farming is commonly associated with adverse environmental impact, and similar effects of ECON and AWEL might be assumed. Our results indicate that, against the backdrop of ECON’s vanishingly small influence, AWEL may be viewed as an ethical perception as opposed to a more rational, ecological perspective. At large, consumers’ intention formation is not about the environment but about avoiding harmful treatment of animals. This conclusion is also supported by the strong impact of AWEL on DIET (f2 = 0.423).
PCE, on the other hand, yields expected results: it does not significantly shape consumers’ dietary behavior, as a variety of reasons, such as feeling morally obligated to avoid meat, may impact DIET. The influence on ATT is substantial, indicating that individuals are convinced that their purchase decisions contribute to the environment.
The small influence of social pressure, in the form of SNORM, appears striking. This finding indicates that extrinsic motivation or seeking social approval is not an essential driver of PI. In combination with NCA findings, i.e., SNORM is not a necessary condition for PI, it plays only a minor role.
Within this study, we primarily aimed at gathering insights into the determinants of consumers’ dietary behavior and the impact of dietary behavior on plant-based food substitutes. Exploratory research provided a first glimpse on the perceived benefits of a plant-based diet (Dyett et al. 2013; Janssen et al. 2016; Lea et al. 2006b; Mullee et al. 2017), but also on the negative associations related to a vegetarian or vegan diet (Corrin and Papadopoulos 2017; Lea et al. 2006a; Lea and Worsley 2001; Pohjolainen et al. 2015). Nevertheless, the importance of the different determinants of dietary behavior and, in turn, its impact on the attitude towards plant-based food substitutes remained unclear.
As extant literature found omnivores to associate a plant-based diet with—inter alia—health concerns (Corrin and Papadopoulos 2017; Lea et al. 2006a; Lea and Worsley 2001; Pohjolainen et al. 2015) and negative stereotypes (Lea and Worsley 2001), it appeared likely that they might not be interested in purchasing plant-based food substitutes. However, we found consumers’ dietary behavior to play only a minor role in consumers’ attitude formation towards plant-based food substitutes, and thus, omnivores, as well as vegans and vegetarians, are equally interested in purchasing plant-based substitutes. This further aligns with our finding that consumers’ dietary behavior is not affected by consumers’ health consciousness, i.e., consumers do not choose a specific dietary behavior due to health reasons, contradicting findings of Dyett et al. (2013) and Lea et al. (2006b). Further, health consciousness does not impact consumers’ attitude towards plant-based substitutes, which is in contrast to preceding findings of the organic food literature (Magnusson et al. 2001; Squires et al. 2001).
Instead, we found animal welfare concerns to be the most important determinant of an individual’s dietary behavior; i.e., consumers choose a specific dietary behavior due to ethical considerations with respect to the humane treatment of livestock. However, as many consumers draw on the standard of animal welfare as an indicator of food safety and healthiness (Harper and Makatouni 2002), following a plant-based diet due to animal welfare concerns might be an altruistic excuse for egoistic motives like health concerns. Only a few exploratory studies (Jabs et al. 1998; Mullee et al. 2017) considered animal welfare as a potential determinant of consumers’ diet.
Consumers do not follow a certain diet to express their environmental concerns or to protect the environment, aligning with exploratory findings of Fox and Ward (2008) as well as Povey et al. (2001), which found environmental concerns to play only a minor role with respect to dietary behavior. Its effect on attitude towards plant-based food substitutes was only marginal. Nevertheless, consumers’ belief to mitigate their environmental impact when purchasing plant-based food substitutes influenced attitude formation, similar to organic food and green literature (Jaiswal and Kant 2018; Vermeir and Verbeke 2008).
Our results suggest several starting points for both organizations offering plant-based food substitutes and policy-makers. As PCE was identified as a major influence on individuals’ attitude towards plant-based food, they believe that reducing their meat intake contributes to environmentally friendly behavior. It is important to help consumers make an informed decision about their grocery purchases by providing data on their ecological impact. Organizations may approach this demand through transparent communication of their supply chains, such as CO2 emissions/carbon footprint, water usage, distance traveled, and other environmentally impactful factors that are easy to grasp and integrate into decision-making. Where it is not feasible to disclose information, e.g., because it is difficult to understand by laypeople, policy-makers may support both organizations and consumers by specifying standardized representation in the form of equivalents. These equivalents may be formulated similarly to ‘The amount of water used for production could fill 100 bathtubs’ (in the case of one kilogram beef) (Institute of Mechanical Engineers 2013). To facilitate comparisons across various products, it is essential to provide standardized equivalents, which may be ensured by policy-making. Research has also found that organizations following environmentally responsible practices can evoke favorable consumer perceptions and may induce more sustainable behavior (see, e.g., the overview presented in White et al. 2019).
In general, however, sustainable goods frequently suffer from the so-called attitude-behavior gap (Rausch and Kopplin 2021), indicating that consumers’ positive attitude towards these products may not translate into action. Hence, from a managerial perspective, it is important to provide boundary conditions that render it attractive to purchase sustainable goods. One critical aspect is the products’ availability within the channels consumers commonly employ for their purchases, such as local supermarkets. Restricted access such as certain products being only available on the organization’s website, thus, is deemed rather counterproductive.
Another critical aspect is that of habit—human beings are creatures of habit. Organizations may make use of this fact by inducing purchases for test purposes to establish a first consumer contact with the plant-based food substitute. Such purchases may be elicited through social media campaigns embracing a dedicated hashtag or featuring consumer posts as a part of the organization’s online appearance, e.g., on Instagram. Other possibilities are lotteries, preferably ones utilizing precise settings such as a holiday season theme, and in-store sales stalls.
Interestingly, consumers’ dietary behavior is not a necessary condition for a positive attitude towards plant-based food substitutes, and further, its influence is also reasonably small. Consequently, individuals may be viewed as potential buyers regardless of their dietary choices, and plant-based food substitutes appear not to be restricted to a market niche.
In the case of social influences (captured in the form of SNORM), which is neither a necessary condition nor yields substantial effects on an individual’s purchase intention, it appears justifiable from a managerial perspective to neglect the variable. However, as green consumption increases, it may well be the case that social influences gain traction and serve, e.g., as a basis for social comparisons, and there is research from other sustainability contexts that find social influence to play a role (Abrahamse and Steg 2013). Organizations creating awareness through marketing campaigns, particularly employing social media channels, enable social processes to kick in, such as spreading word-of-mouth, and may yield benefits when sustainable food in general and plant-based food substitutes, in particular, have become household goods. Still, it is important to bear in mind that the impact of social influences was less substantial than behavioral beliefs, and as such, the latter should be emphasized.
As consumers’ dietary behavior is primarily affected by consumers’ concerns for animal welfare, producers, and retailers of vegan and vegetarian products should bear that in mind and adapt their marketing claims. However, as consumers associate a high standard of animal welfare with healthy products, marketers should link animal welfare claims with health claims.