Global agricultural production today relies heavily on just a few crops, despite the 5,000 food crops estimated to exist worldwide (Royal Botanical Gardens, 2016). Four staple crops (wheat, rice, maize, and potatoes) represent more than 50% of the human energy supply (FAO, 2023). The interaction between urbanization, globalization, social transformations, expanding market sectors, and technological advancements has precipitated shifts in dietary patterns. Contemporary diets are characterized by an increased consumption of energy-dense, protein-rich, and fat-rich foods, which have contributed to rising obesity and overweight prevalence. According to the World Obesity Federation, an estimated 3 billion people worldwide are classified as overweight or obese (World Obesity Federation, 2024). The World Health Organization emphasizes the gravity of this issue, noting that at least 2.7 million deaths occur each year directly due to being overweight or obese (WHO, 2021). This is largely because carrying excess weight significantly increases the risk of developing non-communicable diseases (NCDs), such as type 2 diabetes, certain cancers, and cardiovascular diseases (Knez et al., 2023a). This dietary shift has coincided with a decline in agricultural biodiversity. Agricultural biodiversity is crucial for building resilient food systems, yet its decline increases the vulnerability of food systems to disease outbreaks, extreme climatic events, and market fluctuations (FAO, 2019; van der Sluis et al., 2022). The relationship between dietary patterns and biodiversity is becoming increasingly clear, highlighting the urgent need for a transition to sustainable diets that promote agrobiodiversity, alternative food sources, and more efficient resource use in food production.

In response, global efforts are not only focused on promoting more sustainable farming systems but also on exploring innovative food solutions. There is a growing interest in so-called “novel foods,” including lab-cultivated meat, insect protein, and fortified food products, which offer alternative sources of nutrition with potentially lower environmental footprints (Calabrese and Ferranti, 2018). In parallel with these technological innovations, attention is also turning to strategies that actively contribute to the conservation of agricultural biodiversity. One such example is revitalizing forgotten and genetically diverse crops, known as Neglected and Underutilized Species (NUS). NUS are “useful plant species which are marginalized, if not entirely ignored, by researchers, breeders and policy makers” (Padulosi et al., 2013). The term NUS encompass a wide array of plants, ranging from domesticated, semi-domesticated minor crops, and wild species. NUS is a fluid concept because it is based primarily on their limited or localized use, referring to cases where a crop is a prominent major crop in one country but an overlooked minor crop in another (Padulosi et al., 2013). Although predominantly used for plant species, the term can also be used for animal species (Padulosi et al., 2013).

In light of the rising prevalence of obesity, overweight, and other non-communicable diseases, alongside growing economic and environmental challenges, it is imperative to promote the increased consumption of NUS in dietary regimens. The inclusion of NUS in the diet has been associated with a reduced risk of developing major diseases prevalent in industrialized nations, including diabetes, celiac disease, cardiovascular diseases, and various forms of cancer (Pereira, 2011). They also have considerable potential to enhance overall nutritional status over the course of a lifetime, from pregnancy to old age (Knez et al., 2023a).

Beyond their health benefits, NUS hold considerable potential to enhance human wellbeing in myriad ways. These include providing additional food sources, protecting the environment, maintaining local knowledge, ensuring sustainable use of soil and water, preserving biodiversity, and supporting local economies (Knez et al., 2023a). Furthermore, they exhibit a high degree of resilience to climate change, demonstrating a remarkable capacity to thrive within agroecological niches and marginal areas (Casanova-Pérez et al., 2024; Godlove et al., 2025; Knez et al., 2023a; Padulosi et al., 2013).

Despite the benefits mentioned above, some disadvantageous factors that hinder the inclusion of NUS into consumers' dietary behaviors. One major obstacle is the lack of knowledge surrounding NUS. These food products often have unfamiliar flavor profiles, and there is limited culinary knowledge regarding their preparation. Additionally, there is also a shortage of trained culinary professionals capable of preparing food products from these sources (Knez et al., 2023a). Furthermore, there is currently a significant gap in our understanding of the conservation, cultivation, genetic profile, post-harvest handling, and marketability of these plants (Knez et al., 2023a; Mondo et al., 2025; Padulosi et al., 2021). Additionally, there is insufficient baseline knowledge and awareness of NUS's nutritional, health-protective, and health-promoting properties (Knez et al., 2023a). This shortfall is attributed to the limited scope of existing research, neglect of policymakers and marginalization by the Green Revolution (Padulosi et al., 2021). Another key factor limiting the inclusion of NUS in diets is their limited cultivation due to lower yields compared to major commercial crops (Padulosi et al., 2021). In addition to these knowledge-related and technical barriers, there is also a social aspect that influences NUS consumption. NUS are often perceived as symbols of rural poverty and underdevelopment, which can discourage people from including them in their diets (Knez et al., 2023a).

Promoting a change in food choice and eating behavior to facilitate the inclusion of NUS into mainstream diets requires a comprehensive understanding of consumer behavior. This understanding, which can be illuminated through a behavioral approach, serves as the foundation for this endeavor. It is essential to explore not only the distinct benefits, knowledge-related, socio-economic and technical barriers, but also the behavioral barriers associated with the inclusion of NUS into mainstream diets. Additionally, it is crucial to identify and analyze current food products, mainstream diets, and nutritional practices as they represent competing behaviors that may limit the inclusion of NUS. Beyond identifying the barriers, the subsequent step involves the formulation of actionable strategies that facilitate NUS's inclusion in mainstream diets. The existing literature on NUS, however, does not adequately address the behavioral barriers to their inclusion in diets, limiting the development of effective policy interventions. In contrast to structural or sociocultural barriers, which are influenced by economic factors such as income and price, and political factors such as food policy and regulation (Chen and Antonelli, 2020), behavioral barriers are more intrinsically driven. These encompass psychological, social, cognitive, emotional and situational aspects that influence consumer decisions (Sayess et al., 2024). The present study seeks to identify behavioral barriers to the inclusion of NUS in mainstream diets and to explore ways to overcome them. It reviews the existing literature to examine how behavioral factors may hinder or limit their inclusion into everyday food practices. To better understand these barriers, the study will utilize the core principles of Prospect Theory (Kahneman and Tversky, 1979). The goal is to gain a comprehensive understanding of NUS consumption. Additionally, the present study will utilize the MINDSPACE Framework (Dolan et al., 2010) and Fogg Behavior Model (Fogg, 2009, 2020) to develop a design for tailoring policy interventions, offering a novel and pragmatic approach to addressing the behavioral barriers to NUS inclusion in mainstream diets. This work is a part of the BioValue Project, an EU-funded project within the framework of Horizon 2020. The project's aim is to encourage the inclusion of NUS into food value chains to improve biodiversity.

As defined in the 2024 State of the Food Security and Nutrition in the World, a healthy diet includes the following four components: diversity (within and across food groups), adequacy (sufficiency of all essential nutrients compared to requirements), moderation (foods and nutrients that are related to poor health outcomes) and balance (energy and macronutrient intake) (FAO et al., 2024). Overall, the nutritional quality food intake has been overlooked for a long time in favor of increasing crop yields to meet the calorie needs of the growing global population. By 2030, an estimated 582 million individuals are projected to suffer from chronic undernourishment, highlighting the significant challenge of meeting Sustainable Development Goal 2 (Zero Hunger). This represents an increase of ~130 million undernourished people compared to a scenario based on the global economy prior to the COVID-19 pandemic (FAO et al., 2024). In addition, the world is not on course to meet the 2030 goal of stopping the increase in obesity. The projections indicate that over 1.2 billion adults will be obese by 2030 (FAO et al., 2024).

Malnutrition encompasses both undernutrition, such as micronutrient deficiencies, and overnutrition, including overweight and obesity (FAO et al., 2024). It significantly increases the risk of various diseases, particularly non-communicable ones like type II diabetes, certain cancers, and cardiovascular diseases (Eckhardt, 2006). Malnutrition is not solely a matter of access to food; it is primarily a problem of insufficient dietary diversity within global food systems (Miller and Welch, 2013). One promising strategy for enhancing dietary diversity, improving diet quality and reducing malnutrition is the inclusion of NUS into regular diets. NUS are often abundant in essential nutrients, including vitamins, minerals, and phytochemicals, which are critical for maintaining good health and providing a broad spectrum of health benefits. For instance, NUS such as green leafy greens, fruits, and legumes, serve as exemplary sources of micronutrients, including iron, zinc, calcium, and vitamins A and C (Ayilara et al., 2022; Scarano et al., 2021; Singh et al., 2023). These species provide alternative nutritional sources, thereby diminishing reliance on a limited selection of staple crops and fostering a more comprehensive dietary framework (Segal and Opie, 2015). As an illustration, wild edible flora such as moringa and nightshade are abundant in vitamins A and C, potassium, and dietary fiber (Sultanbawa and Sivakumar, 2022). Similarly, underutilized legumes like wattle seeds exhibit high protein content and have been evidenced to confer potential health benefits, encompassing anti-inflammatory and anticancer effects (Odeku et al., 2024). The Kakadu plum, an underappreciated fruit endemic to Australia, ranks among the most abundant natural sources of vitamin C, rendering it an excellent supplement for alleviating scurvy and enhancing immune function (Sultanbawa and Sivakumar, 2022). Additionally, NUS are rich in phytochemicals and antioxidants, which are crucial for protecting against chronic ailments, including cardiovascular diseases, diabetes, and certain malignancies (Knez et al., 2023a). As an example, the Natal plum, another underutilized fruit, possesses elevated levels of antioxidants that have been documented to exhibit anti-inflammatory characteristics (Sultanbawa and Sivakumar, 2022).

Anticarcinogenic, antidiabetic, and cholesterol-lowering properties, along with anti-inflammatory, prebiotic, and antioxidative effects of NUS have been reported by many over the years (Knez et al., 2023a; Li et al., 2020; María Ruiz-Rodríguez et al., 2014). For instance, buckwheat effectively lowers the glycaemic index serving as a great option for managing blood sugar levels (Sofi et al., 2023). Lentils are packed with essential micronutrients and can effectively supply sufficient dietary levels, particularly iron (Fe), zinc (Zn), and selenium (Se) (Migliozzi et al., 2015). Sow thistle is very rich in antioxidant properties and boasts antimicrobial effects along with the ability to promote wound healing (Li and Yang, 2018). Tomatoes and white eggplants are rich in bioactive compounds that contribute to their medicinal properties, including antioxidant, anti-inflammatory, and anti-cancer effects (Basudan, 2018; Bin-Jumah et al., 2022). Grass pea is high in protein and can be a valuable food source in regions with limited access to other protein-rich foods (Lambein et al., 2019). All of these examples highlight the benefits of NUS and their potential to support healthier diets, making them a valuable yet often overlooked resource in the fight against malnutrition and in efforts to create more inclusive, sustainable food systems.

In addition to their nutritional benefits, NUS can contribute to broader food system resilience and social equity. By promoting agrobiodiversity and supporting local food cultures NUS has the potential to improve food security, especially in marginalized and resource-limited settings. Urban populations frequently encounter restricted access to a diverse range of nutritious food options, particularly within low-income environments (Ziso et al., 2022). NUS can facilitate dietary diversification by introducing novel and nutrient-dense food items that are often more economically viable and accessible compared to exotic alternatives. For example, in Indonesia, wild edible plants, such as various leaves and fruits, are often consumed as a cost-effective strategy to enhance dietary diversity (Rahayu et al., 2024). NUS can effectively combat malnutrition by supplying essential nutrients that are frequently lacking in staple-based diets. As an example, in Kenya, the incorporation of NUS into school meal programs has been demonstrated to augment the nutritional quality of meals while concurrently mitigating costs (Proietti et al., 2025).

To summarize, the reintroduction of NUS offers a promising avenue to ensure healthier diets, improve dietary diversity and sustainability, ultimately fostering healthier populations and ecosystems. This initiative could catalyze a transformative transition in agricultural methodologies and dietary practices, enabling a more sustainable future in which diverse food sources flourish alongside conventional crops. Such a transition not only strengthens food security but also preserves local cultures and traditions, ensuring that future generations can enjoy the rich array of flavors, nutritional benefits, and long-term health benefits associated with more balanced, diverse, nutrient-rich diets.

The selection of food is the result of a complex interplay of interconnected factors. These factors include individual preferences and aversions to foods, influenced by sensory attributes such as taste, familiarity, and the emotional aspect of food. Beliefs, attitudes, norms, knowledge, and skills also play a significant role in shaping dietary choices. These factors are influenced by motivation, self-efficacy, and the presence of social networks. Additionally, social and environmental influences, such as resource availability, price, time, food availability, cultural practices, and media influences, also impact dietary decisions (Contento, 2011).

Changing dietary behavior is a complicated process that demands long-term and flexible methods and strategies. There isn't a single theory that is superior in predicting dietary behavior; predictiveness increases when narrower categories of behavior (such as milk consumption) are examined (Baranowski et al., 1999). Enhancing dietary behavior has become a key concern for nutritionists, health practitioners, and policymakers. The intention varies from tackling diseases such as obesity and diabetes to promoting healthier lifestyles. Many policies with this intention assume that people make poor food choices primarily due to a lack of sufficient information. Therefore, enhancing information is suggested as a policy-making strategy to help people make better choices. However, research indicates that policies found upon the premise of rational choice exert a limited influence on dietary behavior (Liu et al., 2014). This is because food choices, like many other decisions, are not driven solely by utility maximization, which can be achieved through solid cognitive and motivational capacity. They are often habitual, tend to be resistant to change, show minimal responsiveness to new information, and are more strongly influenced by situational and environmental factors than by intentions (Baranowski and Wansink, 2008; van't Riet et al., 2011). In this context, understanding how behavioral factors encompassing psychosocial factors and cognitive biases influence dietary habits can improve the design of dietary change interventions (Baranowski et al., 1999; Liu et al., 2014; Melo et al., 2025; Robinson-O'Brien et al., 2009; Shaikh et al., 2008; Story et al., 2008).

A substantial body of research consistently reports that familiarization with food is strongly associated with food choice (Günden et al., 2024; Tuorila and Hartmann, 2020). Being familiar with food builds confidence in what to expect, which can provide a benefit when compared to new or unfamiliar food items (Tuorila and Hartmann, 2020). Individuals often experience discomfort when confronted with unfamiliar food, manifesting as neophobia and/or disgust (Pliner and Hobden, 1992). Increased familiarity with a food item has been demonstrated to enhance the probability of selection in subsequent circumstances, thereby fostering the development of habitual consumption patterns that are integrated into one's dietary habits (Aldridge et al., 2009). The concept of familiarity also provides a framework for understanding how an individual's current eating habits can serve as a predictor of their level of acceptance of unfamiliar food items (BIOVALUE, 2025; Tuorila et al., 1998). This aligns with two fundamental concepts proposed by Prospect Theory, which influence choices: reference point and loss aversion. According to Prospect Theory (Kahneman and Tversky, 1979), people evaluate outcomes relative to a reference point. The reference point may be associated with individuals' present food consumption patterns, as well as with their expectations, attitudes, preferences, habits, experiences, personality, beliefs, values, norms, knowledge and skills (Chen and Antonelli, 2020; Contento, 2011). It serves as a baseline for evaluating outcomes and classifying them as gains or losses. Individuals tend to exhibit heightened sensitivity to potential losses. Categorizing an outcome as loss triggers a tendency to avoid them, known as loss aversion. Loss aversion refers to the preference for avoiding losses rather than acquiring equivalent gains; losses have a more significant psychological impact than gains of the same size (Kahneman and Tversky, 1979). In the context of eating behavior, this implies that the comfort of familiar foods establishes a reference point that makes deviations feel like losses. Consequently, individuals may be reluctant to try new alternatives because doing so is perceived as a loss relative to their established dietary behavior (Günden et al., 2024). This pattern is known as status quo bias, which is the tendency to maintain the current situation even when better options are available (Kahneman et al., 2018), such as when superior NUS alternatives exist. An important implication of status quo bias is sticking with the default option (Liu et al., 2014). For instance, it is difficult to choose a healthier option when French fries served as the default side dish (Roberto and Kawachi, 2014). Defaults often signal what is typical or acceptable, shaping our perceptions of what is acceptable or normal. It can seem reasonable to finish a large portion served as the default at a restaurant, even if it exceeds what one can eat (Roberto and Kawachi, 2014). Another behavioral barrier that may impact the mainstreaming of the NUS is the endowment effect, which is an example of the status quo and is explained by loss aversion (Kahneman et al., 1990, 1991). This phenomenon occurs when consumers assign greater value to staple foods like rice or wheat simply because they have traditionally consumed them, despite the potential benefits of NUS. To summarize, consumers are reluctant to deviate from their established routines or eating habits. Consumers perceive the inclusion of novel food, including NUS, into dietary routines as a relinquishment of their established dietary habits (Fischer and Reinders, 2016; Günden et al., 2024).

A further barrier to inclusion NUS into diets is priming. This is the effect of the consumer's initial information on perception, which is more influential than subsequent learning (Sayess et al., 2024). Therefore, consumers who strongly believe that unhealthy foods are tasty are less likely to consume healthy food, as they assume that a healthy diet is generally unpalatable. Consequently, consumers are anchored on “unhealthy = tasty” (Mai and Hoffmann, 2015; Paakki et al., 2022).

Another behavioral barrier is rooted in present bias, defined as the tendency of individuals to prioritize immediate convenience or gratification instead of long-term benefits (O'Donoghue and Rabin, 1999). Present bias, alternatively denoted as myopia or short-sightedness, makes it more difficult to choose sustainable or healthier options, especially when the consequences of those choices are unclear or only become evident in the distant future (Aibana et al., 2017; Liu et al., 2014). This is why consumers find themselves compromising between the short-term hedonic goal of eating tasty food and the long-term utilitarian goal of eating healthy food (Mai and Hoffmann, 2015; Paakki et al., 2022). Lowe and Butryn (2007) advanced the notion that consumer food consumption is predominantly driven by pleasure rather than caloric needs alone (Lowe and Butryn, 2007). Moreover, it is contended that the majority of food intake in contemporary society is driven by factors other than energy deprivation, leading to the emergence of pleasure hunger (Mankad and Gokhale, 2023). This explains the concept of “hedonic hunger,” which refers to an individual's excessive preoccupation or desire to consume food for the sole purpose of pleasure, regardless of physical hunger (Espel-Huynh et al., 2018). Hedonic hunger may lead consumers to eat more unhealthy foods rather than include NUS in their dietary habits. Additionally, seeking short-term gratification from food can easily trap individuals in a “hedonic treadmill.” When familiar, high-calorie options are readily available, it can create a cycle of dependence, causing people to associate food with comfort rather than nourishment, especially in anxiety-inducing consumer environments (Carlisle and Hanlon, 2014; Sayess et al., 2024). This means that while indulgent meals or novel food experiences may bring momentary pleasure, the satisfaction quickly fades, leading individuals to seek more. This constant pursuit encourages overconsumption and mindless eating, forming a habit that is difficult to break. Hedonic hunger can be considered in conjunction with scarcity. Scarcity, as defined by Mullainathan and Shafir (2013), refers to the state of having fewer resources than one perceives as necessary (Mullainathan and Shafir, 2013). This concept is influenced by both the available resources and individual tastes. Furthermore, the feeling of scarcity in food consumption may depend on not only on what is physically available but also on what others are perceived to be eating (van Rongen et al., 2022; Walker and Pettigrew, 1984). The feeling of scarcity is distinct from its physical reality. Therefore, the feeling of scarcity can trigger the fear of missing out. The phenomenon of “Fear of Missing Out (FoMO)” is a prevalent concern that individuals experience when they believe that others are enjoying rewarding experiences in their absence (Przybylski et al., 2013). In the context of food consumption, individuals persist in the consumption of unhealthy foods due to the apprehension of forgoing the gratification and enjoyment derived by others from food. Consumers may be inclined to consume tasty foods so as not to deprive others of the pleasure they get from eating, and when offered alternative foods such as NUS, they may fear missing out on the tasty, high-calorie, sugary foods that others consume.

Many people find it difficult to resist tempting foods in today's food environment, where high-calorie, unhealthy foods are cheap and easily available (Stok et al., 2014b). Moreover, food consumption often holds significant social meaning for individuals, further shaping their dietary choices. The impact of the social environment on dietary habits has been extensively documented (see Higgs, 2015; Higgs and Thomas, 2016). Specifically, the food choices of others and the amounts that those in the surrounding environment consume have a strong influence on food consumption decisions (Higgs, 2015). The presence of other individuals in the environment during food decision-making, when eating, or when making food choices has a significant impact on behavior (Higgs, 2015). On the other hand, it is important to note that social influences operate in both directions. The presence of others reliably increases eating, a so-called social facilitation effect, or decreases eating, an impression management effect depending on the situation (Herman et al., 2003). Previous research shows that people make more choices and eat more when they eat with friends than when they eat alone. This effect does not apply when people eat with those they are not acquainted with (Ruddock et al., 2019). On the other hand, some evidence suggests that an unhealthy eating partner may have a negative impact on the selection and consumption of healthier low-energy-dense foods (Robinson et al., 2014a). The acknowledgement of these significant influences on intake is crucial for the maintenance of a healthy diet (Vartanian et al., 2008).

Social norms are defined as behavioral expectations or rules that are in a society or group (Dolan et al., 2010). Descriptive social norms represent one of two primary classifications of social norms, offering insight into the behaviors that are considered typical or acceptable within a given social context. In essence, descriptive norms articulate the behaviors exhibited by members of a given group. The other type of social norms is known as injunctive norms. In contrast to descriptive norms, injunctive norms prescribe behavior by indicating what behaviors are approved or disapproved of by fellow group members (Stok et al., 2014b). In the context of eating behavior, descriptive norms refer to what one's peers, friends, colleagues, and family typically eat, while injunctive norms relate to what one believes they should eat. Together, these norms shape what is considered acceptable or desirable within a social group. In this regard, the concept of social eating norms can be understood as a set of perceived standards concerning the amount of food or specific food choices for members of a social group. Deviating from these norms can lead to discomfort, embarrassment, or fear of disapproval from others (Higgs, 2015), making individuals reluctant to include certain foods in their diets (Stremmel et al., 2021). Social norms can also signal which dietary practices are viewed as healthy or unhealthy, further influencing food-related decision-making (Robinson et al., 2014b).

Despite behavioral and structural challenges, some NUS have been successfully reintroduced into contemporary diets. One well-known example is quinoa. A crop native to the Andes, quinoa has become commercially cultivated in over 90 countries, including many in Europe, due to its adaptability and recognized nutritional value (Bedoya-Perales et al., 2018; Chevarria-Lazo et al., n.d.; Costanzo, 2021). Its global success illustrates how underutilized species can gain mainstream attention when supported by research and favorable traits like genetic diversity. Another example is spelt. Spelt's recent rise in popularity has been attributed not only to its suitability for low-input, particularly organic, farming and high market value (Winnicki and Żuk-Gołaszewska, 2017), but also to its association with gourmet cuisine and the broader revival of traditional food practices, as seen for example in Spain (Alvarez, 2021). Additionally, its versatility in baked goods and widespread availability as flour have contributed to its integration into diets (Alvarez, 2021). The idea that spelt's popularity reflects its nutritional superiority remains an open question, as current evidence does not clearly differentiate it from common wheat (Alvarez, 2021; Kandić et al., 2023; Sugár et al., 2019).

We conducted a narrative literature review using peer-reviewed studies from the Web of Science and Scopus databases. Grey literature was excluded to maintain a focus on peer-reviewed sources, ensuring a higher level of methodological rigor and credibility. The search was limited to studies published in English to ensure consistency in interpretation and to align with the language proficiency of the research team. Our search focused on studies published between 2014 and 2024. To capture the broadest range of relevant studies, we used multiple keyword combinations related to NUS. The initial search results were then refined using a list of terms associated with consumer research on NUS. A third filtering step involved incorporating the terms “barrier” and “obstacle” to focus specifically on constraints in this context. This stepwise process resulted in the following screening query: TITLE-ABS- KEY (“underutilized crop” OR “undervalued crop” OR “neglected crop” OR “neglected and underutilized crop” OR “underutilized plant” OR “undervalued plant” OR “neglected plant” OR “neglected and underutilized plant” OR “underutilized species” OR “undervalued species” OR “neglected species” OR “neglected and underutilized species”) AND (consumer OR market OR demand OR consumption OR “value chain” OR “supply chain”) AND (barrier OR obstacle). The initial query yielded 19 studies after removing duplicates. We excluded studies that focused solely on characterization, cultivation, sensory, or nutritional aspects and lacked content related to consumer research. The remaining 7 studies were included in the review and examined in detail. An inductive approach was used to identify the factors from each study that contribute to the formation of behavioral barriers to the consumption of NUS. Utilizing the core ideas of the Prospect Theory, the extracted information was analyzed and organized considering informational and cognitive constraints, as well as contextual factors, including social influences and situational factors, all of which play a role in shaping barriers to the inclusion of NUS in mainstream diets.

The main objective of this review was to uncover the behavioral factors that hinder or constrain NUS consumption, aiming to provide insights into the design of policy interventions or marketing strategies that encourage their inclusion into mainstream diets. This serves the ultimate goal of encouraging NUS cultivation by stimulating demand for NUS. This section presents the findings of a detailed review of 7 peer-reviewed studies focusing on NUS and highlights the factors related to their consumption. The next subsection summarizes the main characteristics of NUS as depicted in the reviewed studies. The subsequent subsections present and discuss the NUS consumption-related behavioral factors mentioned or evaluated in these studies. Suggested strategies to address the related barriers are briefly introduced at the end of each subsection and further elaborated in the practical implications section.

Revitalizing NUS is gaining attention as a strategy to enhance agricultural resilience, improve nutrition, and reduce dependence on a narrow range of staple crops. However, despite their potential benefits, NUS remain marginalized in consumer diets due to a range of interrelated psychological, cultural, and structural factors that together constitute behavioral barriers to their inclusion in mainstream diets. This review has examined the existing literature to identify the key factors contributing to behavioral barriers that hinder the broader integration of NUS into everyday food practices.

This review highlights the complex interplay of cognitive, cultural, and situational factors that shape the behavioral barriers to NUS consumption. Familiarity consistently emerges as a central determinant of acceptance. The limited familiarity can pertain to various aspects of the products, including their taste, methods for handling and cooking, nutritional value, and their role in biodiversity conservation (Dhakal et al., 2024; Pieterse et al., 2023; Van Loon et al., 2021; Verner et al., 2023). However, the findings also indicate that increased familiarity does not necessarily lead to acceptance. When consumers have some degree of familiarity with NUS, they might perceive its consumption as “risky.” The associated risks stem from multiple factors. First, consumers often associate NUS consumption with social risks, due to the perception of products being culturally incompatible with modernized societies (Knez et al., 2023b; Sanders et al., 2015; Van Loon et al., 2021). Additionally, consumers perceive convenience-related risks, as incorporating NUS into their diets may increase mental effort that can deter even motivated individuals from adopting NUS (Knez et al., 2023b; Lawley and Birch, 2016; Pieterse et al., 2023; Sanders et al., 2015). This combination of factors underlying behavioral barriers suggests that strategies aimed solely at increasing familiarity, such as providing information about health and environmental benefits, may be insufficient. These barriers are further reinforced by market-related limitations, including the limited availability of NUS due to limited or inconsistent supply (Lawley and Birch, 2016; Pieterse et al., 2023; Van Loon et al., 2021). Additionally, the lack of clear quality standards or regulatory frameworks or interpersonal trust might undermine consumer trust (Lawley and Birch, 2016; Pieterse et al., 2023). The potential for NUS-based products to face intense competition in the marketplace further complicates their successful integration (Lawley and Birch, 2016; Pieterse et al., 2023). The market already offers a variety of convenience products that emphasize different aspects of sustainability and healthy attributes, making it more difficult for NUS to stand out.

This review offers a novel contribution by showing that lasting dietary change requires not only information, but also a restructuring of the decision-making environment to make sustainable and nutritious choices simpler and socially accepted. To successfully reintroduce NUS into mainstream diets, the food system must shift from merely informing consumers to actively reshaping behavioral environments through targeted, evidence-based interventions. Only then can we address both the nutrition crisis and the erosion of agricultural biodiversity.

While the increasing inclusion of certain NUS into everyday diets is a promising development, it should be interpreted with caution. Prioritizing the use of only a few varieties, while excluding others, may further endanger the diversity necessary for resilient farming systems (Sanders et al., 2015). As seen in the case of quinoa, the risk of turning NUS into monocrops raises sustainability concerns (Bedoya-Perales et al., 2018). On the other hand, in the case of spelt, overstated health claims may lead to misconceptions about their benefits (Alvarez, 2021). NUS should be seen as complementary to traditional alternatives rather than as substitutes; otherwise, the structural problems underlying current food systems are likely to persist. Moreover, the rapid commercialization of NUS may exacerbate existing inequalities, particularly in rural areas where communities are more vulnerable to shifts in market dynamics (Bedoya-Perales et al., 2018; McDonell, 2021). Future research is needed to examine the broader social and environmental impacts of NUS integration beyond the cultivation phase, with attention to maintaining wider crop diversity and considering the responses of consumers, farmers, and supply chain actors.

This study demonstrates that our understanding of the behavioral factors influencing NUS consumption remains incomplete and warrants further investigation. While previous studies have identified several non-structural factors limiting NUS consumption, the behavioral aspects underlying NUS adoption have yet to be thoroughly explored. This gap is further complicated by the heterogeneity of NUS consumption, as the cultural significance and local knowledge tied to these foods can differ substantially across regions and communities. Future research could concentrate on advancing our understanding of key areas, such as the role of cultural norms in reintroducing NUS into diets across different cultural contexts, strategies for promoting NUS amid competition from conventional products, and the supply chain factors that could support their successful integration to the market.

The present study is not without limitations. First, the review was based on a limited number of peer-reviewed studies, which may not fully capture the breadth of existing knowledge, particularly grey literature or locally specific studies that may offer additional perspectives. Second, the studies included in the review are diverse in their methods, geographic focus, and the context-specific factors contributing to the neglect of NUS. This limits comparability and generalizability. Third, the review focused primarily on behavioral barriers at the individual level of consumption, and thus did not examine the roles of producers, supply chain actors, or institutional stakeholders who also shape the integration of NUS into food systems. These limitations point to the need for more comprehensive and interdisciplinary research to deepen our understanding of NUS adoption across contexts.

Although the primary focus of this study is on behavioral barriers and interventions, it is important to acknowledge that structural factors, such as distribution systems, affordability, and regulatory gaps, also shape the landscape for NUS promotion. With this in mind, this section explores various behavioral intervention strategies to overcome resistance to change and foster long-term improvements in dietary habits that include NUS. The Fogg Behavior Model (FBM) will serve as the framework to elucidate the mechanisms underlying behavioral change, while the MINDSPACE Framework will be utilized as a nudge design instrument.

According to the Fogg Behavior Model (FBM), behavior manifests when three elements converge: motivation, ability, and prompt (also referred to as prompts) (Fogg, 2009, 2020). Motivation refers to the individual's desire to engage in a specific behavior. Ability (also referred to as capacity) reflects the individual's capacity to execute that behavior, influenced by factors such as time, money, physical effort, mental effort, and routine. Lastly, prompts act as cues that trigger the individual to initiate the behavior. FBM further posits a compensatory relationship between motivation and ability; a deficiency in one can be offset by a sufficient level in the other. This interplay can be illustrated as an indifference curve, with prompts positioned above the curve effectively eliciting behavior, while those situated below fail to do so (Fogg, 2009, 2020). Each of these elements can be understood through three dimensions: the individual involved, the action taken, and the context in which behavior occurs (Fogg, 2020). For example, motivation can arise from a combination of personal factors, the perceived outcomes of actions, and the decision-making environment, such as social norms. Similarly, ability is related to personal skills, the ease of the action, and the tools and resources available in the decision-making environment. Finally, prompts can be designed to target any of these elements: the person, the action, or the decision-making environment (Fogg, 2020).

A “nudge” encompasses a range of interventions designed to subtly guide individuals toward desired behaviors by modifying the surrounding environmental factors or altering the presentation of available choices (Janusch et al., 2018; Thaler and Sunstein, 2008). The primary aim of these nudges is to overcome behavioral challenges and promote improved social and individual outcomes without imposing any requirements or limitations. As a design tool, we utilize the MINDSPACE Framework, developed by Dolan et al. (2010). This framework identifies the following nine key ideas that shape human behavior:

We combined the FBM and MINDSPACE concepts to derive a design for developing nudges that specifically encourage NUS consumption. Our design is grounded in the core principles of the FBM, which suggests that behavior change prompts (nudges, in our model) must include balanced levels of motivation and ability elements and that change occurs across three behavioral dimensions (person, action, and context). The motivation and ability elements are operationalized through the nine MINDSPACE ideas. The design identifies segmentation by age groups, lifestyles, and health issues as an important design factor that should be carefully considered.

We adopted the following procedure to develop the design. First, the three dimensions of behavior change have been formulated in relation to their role in NUS consumption behavior. Then, their relationship to the behavioral barriers identified in this study was mapped. The person dimension focuses on enabling consumers to self-trigger NUS consumption, the action dimension emphasizes using existing anchors associated with NUS consumption, and the context dimension involves incorporating or tailoring the elements within the decision-making environment. Following this, each MINDSPACE idea has been systematically integrated into the design by assessing its function to alter eating behavior taking into account both the ability and motivational aspects within these three dimensions. Messenger pertains to nudge itself within our design. Incentives, norms, ego, priming and affect are related to interventions that increase motivation for NUS consumption. Defaults, salience and commitment are linked to influencing the ability to adopt new eating habits. They typically reduce the mental effort required to engage in the desired behavior or help overcome present bias. Within the person dimension, priming, affect and salient can be beneficial. Norms, ego and commitment can be particularly effective within the interventions targeting the context. Lastly, incentives and defaults may work together to simplify the action itself or to shift perceptions regarding the outcomes of consuming NUS. Accordingly, Table 2 illustrates which behavioral barriers can be addressed and how. The table should be interpreted as follows: for instance, if a behavioral barrier related to availability, convenience, or habits identified in the action dimension is targeted, the nudge (i.e., prompt) should use existing anchors associated with NUS consumption (such as routines). In this case, a combination of incentives and defaults may be used to simultaneously address both motivational and ability-related elements of behavior.

Based on Table 2 and Figure 1 provides a few examples of nudges as prompts aimed at Western urban populations, targeting the inclusion of NUS in their diets. In subsequent discussions, we will discuss some of these in detail. This will be preceded by a brief section that provides an overview of a commonly utilized design technique known as framing.