**1. Introduction**

With a global population expected to reach 9 or even 10 billion by the year 2050 and natural resources for food production already scarce in many parts of the world [1,2], humankind is facing a serious challenge: how can we feed everybody? The scientific community has presented various strategies for using current resources to increase the sustainability of food production without using more agricultural land. The main strategies are dietary changes to plant based alternatives, improvements in technology and management and reduction in food waste (e.g., [3,4]). These measures call for changes on the part of both industries/retailers and people involved as customers and as scientists. We investigate several current trends in European thinking about food, seeking to link the various factors involved in consumer acceptance of new dietary elements that are of interest from a sustainability standpoint.

The process of industry innovation is closely linked to the availability of new products on the market. To create consumer demand, new food product launches must combine technological innovation with a series of social and environmental changes, large and small [5]. Indeed, innovation is born from the continuous interaction between the food industry and the institutional and social context in which it operates: it is an opportunity to meet the needs of citizen-consumers, while also responding to emerging social challenges such as environmental sustainability and animal welfare [6–10]. By contrast, research on market trends in food choices shows that there is some resistance to innovations and confirms the stability of decision-making processes that proceed from inertia. Consumers themselves are the biggest obstacle to innovation in the food sector. By definition, an innovative food entails a change from known characteristics, and this tends to clash with habit-bound consumer behavior. This makes many innovations in the agri-food sector incremental rather than radical [7].

As the literature shows, however, it is not always easy to distinguish between cases where consumers' resistance can be circumvented by improving specific product characteristics [11], and cases where resistance is more deeply rooted, as it is linked to specific ideologies about food and is thus not readily overcome. Accordingly, it can be useful to analyze the various facets of food neophobia, or "human unwillingness to consume unfamiliar food" [12], which cuts across the technological challenges now facing the European food industry. As food neophobia can be elicited by a wide range of foods in an increasingly demanding and specialized food market, it can be a major obstacle for producers and consumers alike. Knowing which products are generally associated with neophobia, and which details of the products trigger it is important because it can provide the industry with insight into how to overcome or curb sales resistance. It is equally important to understand whether food neophobia is just an extreme situation, a clinical condition consisting of unjustified rejection of unfamiliar food products, with no logical justification for the adverse emotional reaction of disgust and refusal, or whether it reveals an ingrained attitude that may extend to a wide range of situations.

We will take a closer look at neophobia in order to analyze the construct, understand the instruments whereby it is measured, and explore the situations to which it applies. In fact, neophobia is marked by an underlying "mistrust" of foods that have never been tasted, and is probably linked to a pre-coding of food in a rigid visual schema. Above all, however, it is associated with food's olfactory impact, which jeopardizes its acceptability [10]. This clinically extreme condition mainly affects children and elderly adults, and thus does not seem to involve people who are active purchasers-consumers.

This review of studies on the subject highlights some of the limitations of using the term indiscriminately to explain consumer choices in general. The literature seems to show that feelings of "fear" or "disgust" towards the new in many cases reflect very specific ideological or value choices, which may cause the individual to take up positions in favor of environmentalism, animal welfare or ecology or simply because an individual is clinging to tradition. Thus, we can understand the reasons for avoiding or rejecting a food category only if we identify the consumer's underlying "food philosophy". Moreover, it is only in this way that we can circumvent avoidance and rejection. Confining ourselves to investigating food avoidance behavior could lead us to mistake what is in fact disdain or rebellion for fear. For this reason, our literature review will go into the details of some of these value positions, using other constructs linked to the type of diet chosen to investigate different consumer attitudes to genetically modified organisms (GMOs), cultured meat and edible insects.
