Martina Tuscano¹

Claire Lamine²

Marine Bre Garnier³

Fostering responsible food consumption: a framework combining practice theories and pragmatism applied to an institutional experimental tool

Keywords:

Consumer demand is considered a major driver in the food systems transitions and food policies have become characterized by a variety of attempts to steer food consumption by increasing consumer responsibility. However, there is a gap between the way to deal with sustainable consumption goals, and related forms of responsibility, in the institutional sphere and at the household scale. This gap reflects the disjunction between the normative aim of these policies and the cognitive and practical resistances in changing habits. This paper addresses the responsibility concerns pursued by an institutional experimental tool implemented by local institutions and based on collective experimentation. It draws on an in-depth study and ethnographic survey of two editions of the program implemented in two sites in south-eastern France. Combining practice theories and pragmatist sociology, we propose an analytical framework based on the key phases of habit change (disruption, problematisation, experimenting) and components of social practices (meanings, competences, artefacts). Our results suggest that this experimental tool, through cognitive and practical activities, allows for collective problematisation and experimentation which, in turn, allows for a greater reflexivity about one's own habits and stimulates the integration of new practices. In spite of the fact that the responsibilisation processes fostered remain at the household level, collective questioning and experimentation can both highlight what inhibits habit change and enable transformative change at this level. However, changes at a broader level would require the involvement not only of consumers but of much more diverse food system actors.

Introduction: Consumer Responsibility and Sustainable Food Practices

The transformation of the food system towards greater sustainability is increasingly considered as a major challenge requiring radical changes. However, who is responsible for these shifts and by what means they have to be undertaken is a matter of debate. In the media and public discourse, the consumer is granted environmental responsibility, especially regarding food consumption, based on the assumption of a direct cause-and-effect relationship insofar as their choices would directly lead to an environmental shift [START_REF] Halkier | A practice theoretical perspective on everyday dealings with environmental challenges of food consumption[END_REF]. Likewise, in public policies, solutions for shifting towards a more sustainable model are often attributed to consumers. Indeed, national governments have taken up this emphasis on environmental responsibility particularly after the 1992 Rio Earth Summit through environmental guides such as Agenda 21, and try to encourage citizens to change their behaviour in favour of the environment [START_REF] Hobson | Environmental responsibility and the possibilities of pragmatist-orientated research[END_REF]. However, there is a gap between the ways to conceive and deal with sustainable consumption goals, and related forms of responsibility, in the institutional sphere and in the private one. This gap reflects the disjunction between the normative aim of public policies and the cognitive and practical challenges of changing habits for consumers.

In the alternative food networks (AFNs), the question of "responsibility" is often addressed by developing forms of reconnection between producers and consumers so as to tackle together the environmental concerns linked to production and consumption [START_REF] Goodman | Alternative Food Networks : Knowledge, Practice, and Politics[END_REF][START_REF] Grasseni | Beyond Alternative Food Networks: Italy's Solidarity Purchase Groups[END_REF][START_REF] Renting | Building food democracy: Exploring civic food networks and newly emerging forms of food citizenship[END_REF]. In this regard, the AFN literature has highlighted the learning processes allowing greater consciousness on reciprocal interdependencies based on more direct relationships among local food systems' actors [START_REF] Brunori | On the New Social Relations around and beyond Food. Analysing Consumers' Role and Action in Gruppi di Acquisto Solidale (Solidarity Purchasing Groups)[END_REF][START_REF] Lamine | Settling Shared Uncertainties: Local Partnerships Between Producers and Consumers[END_REF] or, on a broader food system scale, transformations fostered by social movements focused on agroecology and/or food sovereignty [START_REF] Ferguson | Latin American Agroecologists Build a Powerful Scientific and Social Movement[END_REF][START_REF] Rosset | Food Sovereignty and Agroecology in the Convergence of Rural Social Movements, in: Alternative Agrifood Movements: Patterns of Convergence and Divergence[END_REF][START_REF] Stassart | The generative potential of tensions within Belgian agroecology[END_REF]. Regarding the institutional sphere, another strand of literature has explored how public institutions take into account environmental issues in the formulation of policies seeking to steer citizens' consumption [START_REF] Rumpala | La « consommation durable » comme nouvelle phase d'une gouvernementalisation de la consommation[END_REF]) towards more "responsible consumption" and more sustainable diets [START_REF] Dubuisson-Quellier | La consommation engagée[END_REF][START_REF] Dubuisson-Quellier | Why are Food Practices not (More) Environmentally Friendly in France? The role of collective standards and symbolic boundaries in food practices[END_REF]. These authors showed that this institutional framing most often relies on the postulate that the responsible consumer considers the consequences and effects of his/her private consumption in terms of possible changes in the food systems. Accordingly, recent policies have sought to shape food consumption as an expression of citizenship by implementing responsibility and accountability processes [START_REF] Lockie | Responsibility and agency within alternative food networks: assembling the "citizen consumer[END_REF].

While in the alternative food networks changes and learnings are often explored not only at the individual but also at the collective and systemic scale, public policies mainly address them at the individual scale [START_REF] Evans | Constructing and mobilizing 'the consumer': Responsibility, consumption and the politics of sustainability[END_REF]. However, both AFNs and public policy entail the potential risk to reinforce an individualistic perception of responsibility. In other terms, environmental-awareness raising and agri-food initiatives built solely on consumers' understanding of self-interests may undermine the opportunities for transformation [START_REF] Anderson | Transformative agroecology learning in Europe: building consciousness, skills and collective capacity for food sovereignty[END_REF]. Indeed, many so-called alternative initiatives neglect inclusion and accessibility issues for both producers and consumers, despite a growing concern for "just transitions" [START_REF] Lamine | What enables just sustainability transitions in agrifood systems? An exploration of conceptual approaches using international comparative case studies[END_REF][START_REF] Lamine | Territorial agrifood systems: A Franco-Italian contribution to the debates over alternative food networks in rural areas[END_REF]. In order to go beyond a solely consumer-centred and individualistic vision of change, this paper examines the extent to which an institutional experimental tool, i.e. the "Positive Food Families Challenge" (Défi Familles À Alimentation Positive), hereafter the Challenge, aimed at encouraging consumers to adopt more sustainable food consumption habits and enhances responsibility processes through collective experimentation.

Our choice to use the wording "institutional experimental tool" directly echoes the "classical" scientific meaning of experimentation: indeed, this tool relies on i) a preliminary hypothesis made by the designers of this programme (i.e., learning processes generate changes in visions and practices); ii) the designing of a protocol (based on a series of sequences and workshops) and iii) the evaluation of the effects of the tool (based on the evaluation and monitoring of concrete changes in eating habits). We studied the implementation of this tool, which was initially set up by a civil society organization involved in organic agriculture and later taken over by local policies, in two regions in the south of France. In both cases, this implementation was funded by local institutions and based on the voluntary participation of households. We first analysed how habits and changes in food practices occur during the participants life course and to what extent changes are associated with environmental responsibility stakes. Then, we explored the practical or awareness-raising learnings about food production, food consumption and food systems at large enhanced by this institutional experimental tool. In doing this, we put into perspective learnings resulting from the collective experimental tool with changes in habits occurred during the participants' life course. In order to address these processes, we have set up an original conceptual framework combining practice theories and pragmatism.

This will be presented in section 1.1. Then, section 1.2 will present the methods used for data collecting and how they are analysed in this paper. Section 2 presents the two case studies, the origin of the Challenge and, finally, outlines the sequences of the four Challenges -two editions in two sites -studied. Section 3 outlines the changes of food habits during the participant's life course and the learnings developed during the Challenge. Section 4 analyses how responsibility is framed in the programme and to what extent it relates not only to consumer practices but also to the broader food system and shows how the programme has evolved from the first to the second edition in the two case studies and conveyed the project promoters' visions. Finally, section 5 discusses these results and the potential of our combined theoretical framework.

A Conceptual Framework Combining Practice Theories and Pragmatism

Practice theories is an emergent theoretical field inspired by the work of the sociologist Andreas [START_REF] Reckwitz | Toward a Theory of Social Practices: A Development in Culturalist Theorizing[END_REF] and the philosopher Theodor [START_REF] Schatzki | Social Practices: A Wittgensteinian Approach to Human Activity and the Social[END_REF]. These authors elaborated a theoretical framework placing the "site of social" in practices, in contrast to rational choice theories which understand practices as symbolic realizations of human rationality. In this framework, practice is seen as a routinized behaviour which consists of several elements: body and mental activities, 'things' and their use, knowledge, understanding, know how, emotions and motivational knowledge. Practice theories have inspired theoretical works on consumption [START_REF] Warde | Consumption and Theories of Practice[END_REF] and applied studies in several fields, such as household energy consumption (Gram-Hanssen, 2011), pro-environmental behaviours in the workplace [START_REF] Hargreaves | Practice-ing behaviour change: Applying social practice theory to proenvironmental behaviour change[END_REF] and sustainability stakes in food practices [START_REF] Dubuisson-Quellier | Why are Food Practices not (More) Environmentally Friendly in France? The role of collective standards and symbolic boundaries in food practices[END_REF]. Elisabeth Shove and Mikael Pantzar (2005) have studied the emergence of a new practice by focusing on the circulation and the reinvention of competences, meanings and artefacts, categories that allow investigating the relation between significations, knowledge and the material dimension. This approach hence avoids the classical individualistic accounts of "the consumer" and offers new understandings about how changes in practice occur and can therefore impact food consumption. However, this theoretical framework has also been criticized for overlooking the problems of transformative agency and the very processes of change of practices [START_REF] Miettinen | From Habituality to Change: Contribution of Activity Theory and Pragmatism to Practice Theories[END_REF]. Indeed, it does not consider the fundamental role of experiential dimensions for inducing changes in habitual practices.

In order to reintroduce this key role of experience, we suggest to combine the theory of practice approach with a pragmatist perspective on learnings. The approach developed by the American pragmatist philosopher John Dewey, focused on education, stressed the primacy of practical experience in learning processes and in knowledge. Dewey also suggested that every learning is the result of the undermining of former knowledge and practice [START_REF] Dewey | John Dewey: The Later Works, 1938-1939[END_REF]. As pragmatist-inspired authors have shown, learning processes are involved when a disruption in habit occurs. As a consequence, a reflexive process is engaged, which calls for problematisation and the formulation of hypotheses. Finally, a new experimental habit is tested [START_REF] Buch | Pragmatism and practice theory: convergences or collisions[END_REF]. The notion of habits is hence useful as habits may be seen, from a pragmatist point of view, as intermediaries in human-environment relations [START_REF] Bridge | Habit, experience and environment: A pragmatist perspective[END_REF]. Individual-environment interactions imply not exclusively bodily actions, but also ideas about action (imagination, though experiences) and speech (language and communication) [START_REF] Elkjaer | Pragmatism : A Learning Theory for the Future[END_REF]. These pragmatist concepts have been used to question the environmental stakes in contemporary public policy orienting citizens' behaviours [START_REF] Bridge | Habit, experience and environment: A pragmatist perspective[END_REF], or, with a more phenomenological stance, to address individual food trajectories and show turning points through which changes in food practices occur [START_REF] Lamine | La construction des pratiques alimentaires face à des incertitudes multiformes, entre délégation et modulation : le cas des mangeurs bio intermittents[END_REF]. Drawing from these sociological readings on American pragmatism, we have formalized the following analytical categories that we will apply to our case study in order to understand the learnings processes: habit disruption, problematisation, experimentation.

If pragmatism allows understanding how processes of change occur either in life course or during a collective experience as is the case with the Challenge in our case study, it less informs how habits are modified and new practices involved and to what extent the material dimension of practices may cause changes. In this regard, concepts of theories of practices are useful to explore how changes occur in practices. Practice theories indeed provide insights and theorize how the components of a social practice -competences (know-how, practical and theoretical knowledge), meanings (images, values, etc.), artefacts (objects, technologies, etc.)-can vary and "recruit" new practitioners. In order to inform how knowledge and practical experience may transform habits, these three analytical categories will be combined with the pragmatist ones of habit disruption (how the disruption occurs in practical knowledge), problematisation (what does the habit disruption produces?), experimentation (both at the individual scale along food trajectories, and at the collective scale during the Challenge).

Despite these two conceptual frameworks present several convergences, only a few authors have attempted to combine them [START_REF] Buch | Pragmatism and practice theory: convergences or collisions[END_REF]. In such an attempt, Reijo [START_REF] Miettinen | From Habituality to Change: Contribution of Activity Theory and Pragmatism to Practice Theories[END_REF] suggests that the concept of "habit" would be useful for both addressing the habituality character of practices and the relations between human and environment. Indeed, it is when a habit is no longer working that reflexivity and inquiry occur. Even if other authors agree that practice theories might be enriched by pragmatist concepts such as experience, inquiry and knowledge [START_REF] Bogusz | Experiencing Practical Knowledge. Emerging Convergences of Pragmatism and Sociological Practice Theory[END_REF][START_REF] Buch | Pragmatism and practice theory: convergences or collisions[END_REF], none of these works have addressed sustainability issues in food practices. Our analysis seeks to inform what learnings this experimental tool aimed at favouring more sustainable consumption practices generates and allows. Responsibility processes are here addressed through the learnings that generate changes in consumption or at least a new understanding of food system interdependencies, as these learnings do not necessarily lead to behavioural changes. Responsibility is related here to the idea of considering the consequences of one's actions as a consumer and as a component of a larger system of interdependencies. Our combination of pragmatist concepts and theories of practice, applied to the analysis of the implementation of this institutional experimental tool, will serve as a basis for discussing how the environmental responsibility may be stimulated by institutional programmes based on collective activities and how it is confronted with other individual forms of responsibility such as those linked with nutrition and health issues.

Materials and Methods

Our study is based on a qualitative in-depth survey that combines semi-structured interviews and participant observation. This mixed and ethnographic method gives access to some aspects of food practices less accessible to researchers using traditional interview methods [START_REF] O'connell | The use of visual methods with children in a mixed methods study of family food practices[END_REF]. Indeed, empirical and ethnographic perspectives applied to social practices showed that these are highly connected to each other, pointed out how these connections are shaped, and how new practices may emerge [START_REF] Gram-Hanssen | Understanding change and continuity in residential energy consumption[END_REF][START_REF] Hargreaves | Practice-ing behaviour change: Applying social practice theory to proenvironmental behaviour change[END_REF]. Moreover, qualitative and mixed approaches allow for more in-depth undestandings in consumption changes towards sustainability, to grasp disruption and stabilization conditions in "food trajectories". These ay lead either to turning points or to "routinized reflexivity" in habit reproduction [START_REF] Lamine | La construction des pratiques alimentaires face à des incertitudes multiformes, entre délégation et modulation : le cas des mangeurs bio intermittents[END_REF].

Our qualitative approach explores the conditions supporting the undermining of routinized habits, the involved knowledge and forms of commitment that this implies. We do not merely analyse the changes and the adoption of new practices associated to the Challenge itself, but we relate these transformations to those that occurred over the course of the participants' lives: food trajectories are put into perspective with learnings and changes occurring during the Challenge. In this way, we seek to understand how this institutional experimental tool stands in relation to pre-existing habits. Data collected through interviews and participant observation were analysed with the help of our six analytical categories (habit disruption, problematisation, experimentation, taken from the pragmatist approach; and competences, meanings and artefacts, taken from practice theories). We applied the deductive categories to the collected materials through a manual coding. The first three categories relate to crises, reflections and food practices experimentations (e.g. trying a new diet for health reasons by following nutritional programs). The second group of categories informs the practical dimensions concerned (i.e. learning recipes, becoming familiar with the use of tools or with nutritional science).

To assess these learnings and changes, 23 semi-structured interviews have been conducted at different stages of the Challenge and during both editions of the two case studies. We asked all the participants to be interviewed by e-mail and telephone, and one third of them accepted. As these were mainly families with young children, the majority of refusals were due to a lack of time. Nineteen of the 23 respondents were women, since most of the Challenge participants were women as well, and the average age was 44 in the first editions and 32 in the second ones. Interviews were mostly conducted at the respondents' home and, in very few cases, in neutral locations (coffee shops or public places). The interviews lasted about 1.5 hours each and all were recorded, transcribed and manually coded. The semi-structured interviews were guided by the question of change and stabilization of habits: the pre-established interview guide sought, via a diachronic approach, to explore the situations that led to food transformations during the participants' life course. Hence, they focused on the food trajectory of the participants, on their habits, on the dietary changes that the interviewers experienced in their lives, as well as on the motivations leading them to take part to the Challenge and the effects of this participation on their habits. These data provide information on how changes in eating habits occurred and what practical dimensions have been involved. Therefore, the analysis of transformations in habits and in practical and theoretical knowledge allows to question to what extent these changes are related to processes of responsibilisation of individuals, in relation to what and to whom.

Our analysis is also based on data collected through participant observation during the practical workshops of the Challenge. Participant observation basically focused on practical and theoretical knowledge about food, but also on empirical activities and exchanges that might undermine this knowledge during the Challenge. When the context made it possible, we took notes during these workshops about the content of the speeches of the facilitators and other experts or actors, the verbal exchanges among participants, the activities carried out and the distribution of the tasks. Otherwise, we transcribed our observations immediately after the workshop. These data were analysed using the same categories presented above in order to explore the processes of collective problematisation and experimentation. We could thus analyse the contents conveyed by this institutional experimental tool through discourses and practical activities in order to enhance environmental responsibility in consumption practices. Through both data collected by immersive enquiry and interviews, we analysed how people talk about the changes fostered by the Challenge. This allowed us to put into perspective changes in food habits that occurred during life course and learnings enhanced through the Challenge. In the following sections, quotes are used to illustrate key results of our analysis which is therefore based on two types (and temporalities) of participants' experience: past experience along food trajectories, and the experience lived and shared during the practical workshops. Finally, in order to study the transformations of the Challenge itself, we analysed the adaptation of the workshops that have been implemented by the project leaders and facilitators, in terms of both format and content. We analyse the transformation occurring from one edition to another in order to show the evolution of the facilitators' framings of responsibility and modes of intervention.

Case Studies Presentation

Origin of the Challenge and Case Studies Presentation

The Positive Families' Food Challenge (Familles À Alimentation Positive), hereafter Challenge, originated in the French Auvergne Rhône-Alpes Region where it was launched by the regional organic farmers' organization Corabio in 20121 . Following the success of the first edition, the Challenge has been later on implemented in several places in France. Depending on where it takes place, the Challenge could be implemented by local authorities, farmers' groups, organic supermarkets or even by voluntary citizens' groups. It is based on the voluntary participation of households and aims, through practical workshops, to show participants "that it is possible to eat more organic and local food without increasing the budget". Funding for its implementation can be public or private, and the Challenge can be embedded in a broader territorial agri-food project as one of its concrete actions, as is the case in our two case studies. Challenge-branded initiatives generally benefit from a "starter pack" provided by the founding association, which gives access to a purchase monitoring software, a guide to support activities and communication on the Challenge's official website 2 .

The Challenge takes place over the school year, includes practical workshops led by professionals, and requires the physical participation of participating families. These workshops consist of collective activities of cooking, gardening, discussing about nutrition, visits to farms of local producers, visits to organic and local farmers' shops and analysis of product labels. The sequences may vary, as the text box below shows. Since it is a "Challenge," the evolution of participants' purchasing habits is evaluated between the beginning and the end of the programme. This monitoring is done over two weeks, and consists of entering into an online software the price, origin and type of production (conventional or organic) as well as the type of market place (supermarkets, grocery stores, farmers market, etc.) of all food purchased during this two-week period. At the end of the monitoring, a graphical user interface shows the participants' food purchases with the amount spent for every category. This procedure is the first step for "eating better without spending more" as it aims to show participants their current habits and what they can improve. Participants also have access to the graph showing the purchasing habits of other families in the same team. At the end of the Challenge, the comparison of the participating households' evolution in terms of purchasing habits between the initial and final evaluation indicates the winning group, i.e. the group with the highest margin of progression in terms of organic and local purchases. Despite the fact that the Challenge has a relatively pre-established facilitation guideline, a certain amount of flexibility is granted by the facilitators to adapt the programme to the participants' needs.

Our study is based on a comparative analysis of two Challenges in south-eastern France: one has been held in the city of Mouans-Sartoux, the other took place in the Drôme département. The two case studies were chosen because a Challenge took place in each of them. Moreover, in each of these two areas two editions of the Challenge took place, the first one during the school year 2017/2018 and the second one during the school year 2018/2019. Thus, the two case studies chosen allow for a double comparison: both a comparison on the implementation in two different locations and a comparison between the first and second year of implementation.

The first study case is located in the Alpes-Maritimes département, near the Italian border. The town, with a population of approximately 10,000 inhabitants, has elected officials strongly involved in food issues since the late 1990s. Since 2012, the town has been running a food relocation programme for school catering. This is accompanied by educational actions on sustainable food for students. Since 2016, a territorial food project3 is implemented at the municipal level and foresees the development of a local food strategy focusing on education, agricultural settlements, and the spreading of actions carried out at the city level. This project carries out sustainable food education activities in which the Challenge took place in 2017 and 2018.

The second case study is located in the Drôme, a départment (517 000 inhabitants) in the east of the Rhone Valley in south-eastern France. In this rural area, local authorities have initiated since the 1990s a territorial project later labelled "Biovallée" (literally "organic valley') which fosters a sustainable transition of the territorial agri-food system and of residents' practices through actions in complementary fields, including agriculture and food. In 2016, the local authority, bringing together the municipalities of the territory, initiated a process aimed at developing a local food strategy. The core of the project consisted of identifying the obstacles that hinder producers and consumers from turning to organic farming and food. The first edition was carried out in the Drôme valley area in 2017. Another edition took place in Valence, the main city and capital of the département in 2019, launched by another partnership than the previous one in order to target another audience.

The Challenges' Actions and Objectives

The guiding precept of the Challenge is that a flexible number of households4 (singles, couples, households with children) come together to take up the Challenge of increasing their consumption of local organic products while keeping a constant budget.

In the official Challenge website, the motivations for which people should participate are reported as such: 1) free practical support for making the transition towards a tasty and balanced diet, 2) learn tips and tricks to consume local organic products while keeping the budget under control, 3) meet and exchange with the other participants, 4) find out more about organic farming and know where to buy organic products in one's neighbourhood/city, 5) share recipes for inexpensive local organic seasonal dishes.

During the Challenge, key collective moments are organized for participants (about once a month). Guidelines are provided to frame the Challenge activities and suggest a typical sequence of activities, i.e. 1) a kick-off party to explain the main goals and allow Challenge members to get to know each other; 2) an exchange with a dietitian nutritionist to talk about the interest of organic products and discover vegetable proteins, 3) a cooking class with a chef, 4) an organic farm tour, 5) a game activity on organic farming and a shared meal, 6) organic gardening, 7) food purchase monitoring in order to evaluate the participants' food habits at the begin and at the end of the Challenge.

Nonetheless, the following boxed text with the activity sequences of the four analysed Challenges shows that for each edition the framework suggested in the guideline was adjusted in quite different ways. Some activities were skipped while others were repeated several times. For example, the game activity about organic farming took place in only one edition. By contrast, cooking classes were definitely the most frequent activity along the sessions. Also, some other activities -not suggested in the guidelines-were introduced in the Challenges we observed such as label reading, food waste and gathering and harvesting wild plants.

The sequences of the programmes Mouans-Sartoux 2017/18 -13 households Purchase monitoring -nutrition workshop -organic purchasing markets tour (4) -label reading workshop (added) -4 cooking classes-food waste workshop -eco-friendly and low-budget meals workshop -gardening workshop -spice workshop (added) -"independent" farm visitspurchase monitoring.

Transformation of Habits over the Life Course

The analysis of the interviewees' food trajectories informs the conditions leading to food habits disruption, problematisation and experimentation. A significant number of correspondents stated that major changes in food habits during their life course were related to radical changes in life stages. Leaving the parental home, moving in with a partner, the arrival of a child as well as migration processes seem to go along with the transformation of eating habits. These transformations triggered crisis, hence disruptions, in their eating routines. Participants statements testify that places and type of products are suddenly replaced by other modes of operation. Above all, however, these changes in routines often go along with evolutions of social status (become wife/husband, mother/father, having a career change, etc.). The following account shows that this participant is confronted with the fact that her ancient habits no longer worked in a new context, as she moved to another country and left her family: "I never learned to cook at my mother's house and that's a big problem, it's not good. When I arrived here [in France] I was 30 years old with my husband and I was in charge of cooking. I asked my neighbours how to do that, and how to prepare chorba5 , soups, cakes. I didn't even know how to make bread. [...] I used to invite my women friends home and ask them to show me how to cook. And that's how I learned. " (women, 49 years old, unemployed, Challenge 2018/2019) Indeed, a disruption of former habits occurs because this woman was suddenly confronted with being responsible for someone and switched from the position of the "nourished" to that of "feeder". According to the interviewees accounts, problematisation about current habits may result from changes in life course, and particularly those implying to become accountable to someone or responsible for someone. Along the same way, disruptions may occur when social norms or institutional and medical prescriptions impose suitable habits that are in discordance with current ones, as this account suggests: « Since last year I asked for two years of time off for health reasons and because I was struggling to reconcile two heavy schedules, that of my husband and mine, and because of we have two young children, and because we want to try to move towards local food. » (women, 42 years old, executive, Challenge 2018/2019)

In addition to health motivations, the household organization of food supply, processing and consumption was not suitable for this woman to consider herself as a good "nurturing mother" and led here to temporarily stop her work. Having young children, as in this case and many others, and feeling responsible for them, leads to be willing to feed them with nutritionally correct food, as balanced and "natural" as possible, as is argued by public, medical and media discourse. Hence, many families testify to having radically changed their practices after being confronted with normative information concerning the impact of food (either specific products or chemical components like pesticides) on health:

"When I was at the secondary school I cooked but I enjoyed without wondering if it was health. When I had my kids, I made more mashed potatoes, more vegetables and I was careful to cook it healthier...but I think that what has been radical is the Yuka 6 application: you scan the bar code of your product and it tells you if it's good, moderate or not good and it explains why. I scanned everything I had in my kitchen and in my fridge, and that hurt...that was a year and a half ago...I've been gradually removing all the bad stuff. "(women, 39 years old, executive, Challenge 2018/2019) Correspondents' statement also points out that when existing habits are undermined and problematisation occurs, the participants experiment new food procurement and transforming modes, and test new products. In several collected cases, participants experimented as they were encouraged by tips and practical suggestions conveyed by the family, or by the broader social network (neighbourhood, relatives). Experimenting new food habits involved for a majority of the households surveyed, the introduction of new places for buying food (i.e. local producers), new procurement modes (i.e. local or zero waste grocery stores), new cooking methods (i.e. self-made soups) and, of course, new products (i.e. fresh and seasonal products). However, as the time schedule seems to be a main obstacle for several respondents, households often rely on new shopping modes offered by the supermarkets (such as drive-through systems) or new technological tools aimed at facilitating their choice of healthy products as in the above quote and simplifying the several tasks linked to meal preparation such as food processors. Such food procurement and cooking artefacts allow reducing the time invested in the different steps involved in food preparation. They may also direct the choice, the planning and the preparation of meals in the daily lives of families, as this interviewee reports:

"I'm lucky to have a Thermomix, it's fantastic, and now the children take the cookbook, they love it, my son made a wonderful risotto, it was so good. I make paella, I don't buy it anymore because it's more ecological, it's cleaner, so since we have this food processor, we cook much fresher. We eat dishes that I couldn't cook before, for example lentils. (women, 44 years old, self-employed person, Challenge 2017/2018)

This account shows that if the technological tool mentioned here is used by this family for reducing cooking time, it also allows preparing healthy dishes that would otherwise be complex to cook and, for this respondent, more ecological meals. The food processor is described here as fulfilling this person's requirements in terms of nutrition and sustainability.

Our results highlight that meanings connected to processes of habit disruption, problematisation and experimentation are primarily linked to health, budget and, to a lesser extent, environmental concerns and mostly motivated by arguments concerning the interviewees' nourishing role and the well-being of their family. The consumption-related forms of responsibility, according to the collected accounts, vary according to the life course of individuals. Indeed, while among adults with young children, the feeling of responsibility for the well-being of their family seems to prevail, arguments linked to a feeling of responsibility for the impact of one's food practices seem to come later in life courses. Respondents who appeared most concerned with environmental issues were predominantly highly educated, even though not all highly educated participants appeared as environmentally concerned. In contrast, nutritional concerns seem to affect individuals regardless of their education level. Interestingly, for a good number of participants, environmental arguments are framed through the issue of waste, more than through that of transport (both goods and consumers) or of agricultural practices. The will to buy locally is often justified by economic or social arguments rather than ecological ones, and mostly to support local businesses or producers.

The analysis of changes in food practices along food trajectories shows that following a disruption in habits, often linked to a change in life stage, a problematisation stage leads to experiment or test new habits that appear as solutions towards a more sustainable behaviour. These changes in habits go along with renewed meanings (such as the idea of healthy and ecological ways of eating), with new competences to appropriately perform the new habits, and often also rely on newly adopted artefacts (tools and technologies). While this analysis of changes in the life course reveals problematisation and experimentation processes which occur at the household scale, the following section based on the analysis of the role of the Challenge will highlight the problematisation and experimenting processes occurring at the collective scale, which appears as a main contribution of the Challenge.

The Role of the Challenge's Collective Activities

This section is based on the direct observation of the Challenge's workshops and on the interviews conducted with participants during and after the programme. The analysis is therefore based on the experience of participants during the Challenge, accessed "directly" through participant observation and "indirectly" through their report of this experience, given in ex-post interviews. The learnings enhanced by this experimental tool consist both in forms of reflexivity (problematisation) of the participants about their own household's consumption habits and in practical adjustments suggested by the collective activities (experimentation). For a large majority of participating households, the Challenge occurred in a moment when families were already questioning their habits and wished to go towards more suitable food habits. For some families this meant better know the nutritional properties of food and better balance their diet as well as reduce the share of fat or sweet products, for others it meant to reduce plastic packaging, consume more organic food or less meat. Motivations might be different but all participants questioned their own habits which led them to look for possible solutions through their participation in the Challenge. Following our grid of analysis, almost all households were in a phase of habit disruption, and the Challenge seems to both strengthen the questioning of families about their actual habits (problematisation), and allow the experimentation of potential new habits.

Among the learnings outcomes highlighted, we can distinguish between knowledge that participants were explicitly seeking before starting the Challenge, and which motivated their participation, and unexpected learnings. In the first case, the competences acquired dealt with both theoretical knowledge, i.e. about nutritional components, and practical one, i.e. how to use new products or use differently already-known ones. For example, some participants mentioned learnings about objects or ingredients that they may already have in their kitchen, but that, if used differently, may shorten preparation times or avoid using unhealthy products. Such learnings thus relate to artefacts -kitchen utensils or ingredients -which are reinvested with renewed functions and consequently new competences. For example, a participant related that she learned to prepare a pie with leftovers and to use a vegetal thickener consisting of flour and water instead of sour cream, which limits the use of animal fats and is healthier. The Challenge concretely questions and modifies the materiality of practices, namely through the discovery of new food retail stores, new artefacts (or renewed use of already known ones), and modes of organization in everyday life. In addition to the retailers visited during the workshops, participants discover other retailers based on other participants' experience: zero waste grocery store, CSA 7 boxes, producers' stores, etc. Several locations were suggested by members of the groups and almost all participants decided to test at least one new supply location. Another common element to many surveyed people is the change in organization and weekly planning for procurement, processing and consumption. These changes in the time schedule or organization are usually aimed at devoting time slots for processing activities in order to reduce the amount of food practice activities, as this couple tells us:

"We buy much less processed stuff. So we've already been planning moments, uh... trying to stick to them. For example, we don't buy kids compote anymore, and every weekend we take the time and make compote. " (woman, over 35, executive, Challenge 2017(woman, over 35, executive, Challenge /2018) ) Even though most of the participants were already going through a questioning phase when they took part to the Challenge, in some cases their food habits were further questioned by the programme. The purchase monitoring carried out at the beginning and end of the Challenge led to highlight not only some habits that participants were already questioning, but also purchase routines they were not conscious about. The monitoring system, which consists of two phases allowing participants to evaluate their own practices, leads them to reflect on their purchases, to consider them through a new analytical lens. After the period of data recording, a graphic interface shows the repartition of the two weeks' food budget between meat, dairy and vegetable, organic or not, local products or not, and according to the places of procurement. These two phases allow for the objectification and the self-measurement of consumption practices. For example, a participant reported that the monitoring process allowed her to quantify her household's consumption and compare it to that of the other participants. She realized that, compared to other families, her household consumed much more meat, and less organic food. Following this finding, she started to buy vegetables from a local producer, where she could buy imperfect vegetables at a minor cost and thus include more and better vegetables in the meals. Another participant explained: "I think that in the "Challenge," the recording of your purchases and especially the graph that shows what you spend the most on is very useful [...] I realized that the majority of products I consume come from the other side of the world." (Women, 38 years old, unemployed, Challenge 2017/2018) In addition to these expected learnings, the Challenge also generated several kinds of unexpected outcomes. Indeed, collective formulation of households' problems and possible solutions result from the collective dimension of workshops and the fact of « doing it together ». The survey shows that the idea of experimenting together, in the sense of collectively contributing to an experience and ensuring its success, is perceived not only as a moment of leisure but also of information exchange between participants. These moments of shared experience during the workshops, as well as outside the workshops, allow the creation of spaces and exchanges among peers specifically focused on food practices at large (including retail stores, week meal planning and easy and healthy recipes). This shared experience is central in the participants' accounts on peer knowledge exchange:

"Be with new people, exchanging tips, seeing that we're all at different levels but we all want to be there. It's not like seeing a documentary at home, you're really with the people who are living it! (Women, 42 years old, executive, Challenge 2018/2019)

The participants are together along the sessions, they not only communicate, exchange recipes, difficulties and stories about their daily experiences, but they also cook, shop and garden together. It allows both collective problematisation of what's not functioning anymore in current habits and collective experimentation. What the Challenge brings to a process of habits change is to transform ordinary activities usually conceived as individual tasks into a recreational moment where knowledge and tips are exchanged in the practical situations where they are useful, and not independently from the moment of practice. Indeed, whether it is cooking, gardening or shopping, all activities usually carried out individually, turning these activities into funny moments involving family members and other participants brings a new perspective to these practices. A participant expressed it in the following way:

"We are in a group, exchanging ideas, discussing with each other. We used to do it before, but now we're really focused on food. What I really appreciate was to cook all together. I'd never done it before. I'm used to cooking with my children, but I don't like adults in my kitchen...and cooking all together was really nice...it made me want to cook with adults [...]" (Women, 46 years old, unemployed, Challenge 2018/2019) The collective dimension thus allows participants to reduce the gap between the recommendations emanating from the media, medical and public institutions, and their implementation, through the sharing of experiences. For both nutritional and environmental issues, it is indeed challenging to bridge the distance between "what should be done" and "how to put it into practice". These experimental spaces therefore offer concrete situations and opportunities where participants learn how to fill this gap. The tips people convey have the distinctive feature of accommodating the elements that participants perceive as constraining. Thus, tips provide people the resources to bypass the constraint and to implement -or at least to test -a new behaviour.

Our analysis shows that the Challenge promotes learning processes that can lead to further question current food habits and to test new ones. As explained above, during the life course of our respondents, changes in food habits are often related to important changes in life stages and, consequently, in social status as well. Health, budget and, finally, environmental concerns are the main motivations inducing disruption, problematisation and experimentation in habits. Moreover, these arguments are primarily linked to the interviewees' nourishing role and to the well-being of their family. In these situations, even though the households' social environments may orient changes and/or suggest solutions, these are most often tested at the individual/household scale. In contrast, the Challenge's activities allow households to collectively formalize problems, make hypotheses about solutions and test new behaviours. However, if the Challenge introduces new competences concerning eating habits and through new artefacts (objects, places, purchasing ways, etc.), the meanings associated to the adoption of new habits mainly remain linked to health, budget and for some participants, environmental issues. Moreover, despite the fact that the Challenge allows for collective practical and reflexive activities that strongly encourage the adoption of new habits, responsibilisation processes mainly address the households scale and little encourage distributed forms of responsibility and systemic perspectives on food consumption sustainability.

Framing Responsibility

This section will analyse how the content of the programme frames the notion of responsibility and at which scale (individual or collective, household or food system, local or global). It will show that this framing of responsibility remains mainly based on health and economic issues rather than on environmental ones, and at the individual and household rather than the collective or food system scale. Therefore, interdependencies and power relations between the diverse components of the food system are infrequently addressed, as are ethical issues and structural inequalities in the global food system. Based on the description of the changes in Challenge implementation from the first to the second year, we will highlight not only how this experimental tool becomes a place for negotiations between institutional ambitions and the resistances linked to the routinized habits of households, but also the existing mismatching between individual, collective and institutional construction of responsibility issues.

Fostering Responsibility at the Individual Scale

Both the objectives of the programme and its content show a strong focus on health, budget and procurement practices. The public formulation of its objective is: 'Eat better without spending more' ('Manger mieux sans dépenser plus'). The aim is to teach consumers what is healthy and organic, how healthier meals and dishes can be prepared, how labelling should be interpreted, what are the local places where basic healthy and organic food can be bought, etc.

Of course, these programmes are talking about sustainable food consumption and the environmental dimension is also strongly present, through the focus on organic and local food, and through activities aimed at raising awareness about food waste and pollution issues. The analysis of the issues that are tackled during the workshops and of the discourses held by the facilitators and the invited experts (or food system actors), allows for a characterization of the framing of this environmental dimension, which appears mainly in terms of impact (of inputs, of packaging, of waste, of meat, etc.). In one of the editions that we observed, a multiple-choice questionnaire was distributed to all participants to test their knowledge about food waste, that was framed in terms of health, environmental and economic impact. The facilitator then pointed the mismatching between participants answers and official data. This led the group to start a conversation about purchasing, conserving and transforming practices that would limit food waste and overconsumption. Therefore, the group immediately redirected the topic illustrated by abstract data to discuss their daily habits and to possible strategies to limit food waste.

Another characteristic of this framing is the focus on organic products. This can be understood by the fact that the programme was initially conceived by an organic organization. Over time the relative balance between organic and local origins changed, in link with a larger controversy, especially around public food procurement, about the origin of organic products (often imported) and the progressive legitimation of a motto like 'organic and local is ideal'. Indeed, in the workshops, participants would often raise debates over the environmental benefits and meanings of organic food. For example, in one of the workshops, some participants expressed the fact that they would favour local and tasty products to imported organic products. They also considered that a good food product may come from a form of agriculture "that could be close to organic farming criteria (chemical free) without having the certification".

Our analysis thus shows that responsibility issues in this programme are framed in terms of impact (both on health, budget and environment), by quantifying practices or actions (e.g. annual food waste), and through products properties that may be related to sustainability stakes (local/distant, organic/conventional farming, direct relationship with the producer, taste, seasonality, etc.). The key hypothesis underlying the programme is that the adoption of new practices will lead to limit both environmental and health externalities. This standpoint little addresses systemic aspects and power relations among the different components of food systems insofar it is based on a cause/consequence relationship between the integration of preestablished criteria (organic and local) and the impact of these consumption turns. Although the programme brought together a diversity of actors of the local agri-food systems during its sequences (producers, shops, CSA dealing with environmental, agricultural and food issues, etc.), none of the four studied editions deeply considered food issues from a systemic perspective. Indeed, in the workshops' contents, the identification of the different actors and components of the food system and of their interdependencies was little at stake either. These programmes lead to a greater participants' consciousness about the capacity to transform their practices at their own, individual scale, but do not really encourage participants to go beyond the prescriptive lessons. In other words, if we consider that the Challenge allows for a collective problematization about daily resistance to food habits change from a consumer standpoint, it less enables collective understanding about the larger changes at the scale of the food system.

Tool Transformation from First to Second Edition

Several key transformations occurred during the implementation of the Challenge from the first to the second year. These changes reflect the function given to the Challenge by its promoters and facilitators, two local authorities, an association of organic farmers and a public Centre for Social Action8 . These transformations from one year to the other highlight not only which transformative role is ascribed to the Challenge, but also which public the project leaders seek to raise awareness of and, vice versa, towards which public they feel accountable.

In both case studies, the public involved changed significantly from the first to the second year, and this was due to an explicit willingness of the organizations that implemented the Challenge. In the first year when it was set up, for practical reasons of lack of time, information was disseminated through parents' networks, local associations or by word of mouth. The result, in both locations, was that most of the participants were already aware of, or even involved in, sustainable food initiatives. The second year, in order to involve supposedly less convinced people in the Challenge, the enrolment process took place in a proactive way and through local associations and organizations with a social purpose. These well-established networks provided levers for involving other profiles of participants in the Challenge. Once again, the facilitators had to avoid any stigmatization risk, since sustainable food issues may be perceived as markers of the upper social classes. Faced with this risk, the facilitators gradually modified the content and classic format of the Challenge.

During the first year, a wide range of activities and discussions during the collective exchanges focused on local and organic food in both case studies. These exchanges sometimes created situations that put the attention on those who were comfortable with these arguments and vice versa led to stigmatize those who were not. Hence, for the second-year workshops in both case studies, the facilitators tried to avoid a vocabulary borrowed from the sustainable development discourses. The content of the activities, as well as the exchanges between participants, was much more focused on ordinary practices. Besides, the funny and participatory nature of the workshops was emphasized and the Challenge which was presented at the beginning of the year as a family activity. The system of monitoring purchases was not adopted by all the families because it was felt to be too restrictive. The handle of the software can be a significant obstacle, and the recording of purchases also requires time and skills that some participants would lack.

The facilitators of one Challenge also wondered about the stigmatization power of the vocabulary and decided not to use the motto 'Positive Food Families Challenge.' Categorizing sustainable food practices as 'positive' imputes, by contrast, a 'negative' label to other practices. The facilitators hence adapted the Challenge to the targeted audience including lowerclass participants. First, they gave up the purchasing monitoring system which had been a pillar of the Challenge since its inception, as it allows participants and facilitators to see whether the Challenge is achieving its stated objectives, i.e. to demonstrate that 'it is possible to increase consumption of local organic products without increasing your budget'. However, this monitoring system was considered too complex system for the participants, and the facilitators wanted to make the Challenge the least restrictive and normative as possible. Along the same lines, one of the facilitators highlighted the need to change the Challenge slogan, originally 'Eat better without spending more,' towards 'Eat well and enjoy yourself without spending more.' Interestingly, no information about this particular Challenge can be found on the official Challenges website. This section points out how the programme promoters and facilitators see this collective experimental tool. Promoters' goals are translated into actions and pedagogic contents aimed at the targeted public. The comparison of the two editions shows that local authorities and local organic associations in charge of the programme seek to enrol new publics (lower social class families) in sustainable food consumption practices in the second edition. This shows the link made by the promoters between sustainable consumption practices and the public expected to be familiar (or not) with these practices. Based on the first years' experience, they assume that in order to involve lower-class families, whom they consider as unfamiliar with these practices, they have to adapt their programme. This is in line with the frequent assumption that sustainable consumption is a marker of upper social classes and shows that local authorities promoting this collective experimental tool perceive themselves as accountable for supporting changes in all the population. According to this standpoint, the Challenges' sequences and contents have been adapted during the second edition for what was seen as an 'unfamiliar public'. As a consequence, the environmental dimension of food production and consumption was much less discussed and the workshops were conducted as recreational and collective activities with the will to avoid a normative view of consumption. Our comparison showed that this explicitly less normative edition has nevertheless allowed for rich processes of problematisation and experimentation and has had similar effects.

Discussion

This paper is based on the observation that there is a gap between the way to deal with sustainable consumption goals, and related forms of responsibility, in the institutional sphere and at the household scale. This gap reflects the disjunction between the normative aim of public policies and the cognitive and practical challenges of changing habits. Our analysis shows that in food habits routines or disruptions, nested forms of responsibility are at stake, that may change depending on contexts, actors, and with regard to what or to whom to be responsible. Indeed, if at the household's scale responsibility issues are much more associated with the family's well-being [START_REF] Lockie | Choosing organics: a path analysis of factors underlying the selection of organic food among Australian consumers[END_REF], the Challenge's aim was to encourage participants to adopt formal and quite normative habits designed as sustainable. In order to understand how changes in practices are put in place (by eaters) or supported (by the experimental tool under study) and in link with which framing of responsibility, we have proceeded in two steps and first studied the changes along food trajectories and then changes linked to the participation to the Challenge.

The analysis of food trajectories showed that most habits disruption processes are in connection with changes in life stages, joining previous studies that have also demonstrated that turning points along consumers' trajectories may go along with profound transformation of eating habits [START_REF] Crenn | Introduction : Repenser et réimaginer l'acte alimentaire en situations de migration[END_REF][START_REF] Lamine | La construction des pratiques alimentaires face à des incertitudes multiformes, entre délégation et modulation : le cas des mangeurs bio intermittents[END_REF]. This analysis also highlighted that these changes occurred with the intention to act directly on one's or one's family's well-being. Indeed, in most accounts, the form of responsibility at stake has to do with responsibility towards oneself, or towards the persons whose "well-being" depends on us [START_REF] Plessz | How consumption prescriptions affect food practices: Assessing the roles of household resources and lifecourse events[END_REF]. However, we go beyond behavioural changes which are mostly tackled in the literature about changes in food diets and propose further insights about the cognitive and material dimensions at stake. Hence, we showed that in food trajectories processes of problematisation are most often managed at the individual or household scale when habit disruptions occur, despite potential new habits may be suggested (or imposed) by the social environment of participants. In these stages, new competences are acquired, artefacts may orient new experimentations in consumption, and often new meanings are integrated.

In contrast, the Challenge allows for processes of collective problematisation through pedagogical and experimental activities and peer-to-peer exchange. Competences acquired during this programme fill the gap between suitable new habits that families aim at and resistance generated by current routines. The Challenge also encourages new questioning and problematisation processes about food habits through practical and general information given during the workshops, and based on the purchase monitoring software which objectifies the participants' daily consumption. The comparison and discussions with other participants, the exchange of tips, the discovery of other "ways of doing" all question the established order of everyday practices. Even though this programme alone is not sufficient to produce radical behavioural change, outcomes may lead to a better understanding of a phenomenon and to increase individual and collective reflexivity. However, the programme and its activities little address the interdependencies within the food system, nor the power relations at stake. This essentially individualized notion of responsibility may be associated with the neoliberal notion of self-responsibility, which contrasts with an ecological model of responsibility based on distributed responsibilities and related-community values actions [START_REF] Lockie | Responsibility and agency within alternative food networks: assembling the "citizen consumer[END_REF]. Moreover, it has to do with the way in which the "consumer" is mobilized by the dedicated institutions or in consumption-related policies [START_REF] Evans | Constructing and mobilizing 'the consumer': Responsibility, consumption and the politics of sustainability[END_REF] and in this case responsibilisation of consumers follows a logic aimed at maximizing self-interest as its motto "eat better without increasing one's budget" testifies.

From a conceptual point of view, this paper advances new perspectives. We used an original conceptual framework combining theories of practice and pragmatist approaches concepts that allows addressing both procedural and symmetric dimensions of habits change. Indeed, the concepts drawn from pragmatism allow understanding how changes occur, through the key stages and processes of disruption of habits, problematisation and experimentation (three successive and consequential phases in the change of habits) thus allowing for a procedural perspective. Our framework also allows a symmetric perspective because the concepts inspired by practice theories enable an understanding of change that considers in an equal way the cognitive and the material dimensions of social practices. Hence, we drew six categories from these two theoretical approaches, respectively meanings, competences, artefacts (drawn from practice theories) and habit disruption, problematisation and experimentation (drawn from pragmatism). These categories proved appropriate to analyse the changes processes in food trajectories and through the institutional experimental tool, both illustrated in Figure 1. The analysis of food trajectories allowed to show which kinds of motivations, know how, and material implications are associated to processes of change in food habits during the life course of interviewees. Responsibility issues at stake are mostly seen at the household scale, and associated to the feeling to be responsible for someone (i.e. our own, children or partner's health) or towards something (i.e. family economy). We demonstrated that changes in food habit are often related to the fact to feel responsible with regards to something or to someone and that this process not only implies cognitive capacity to question, formalize and test potential new habits but also require the integration of new meanings, competences and artefacts. This study thus confirms that emergence of new habits go along new socio-cultural understandings and norms, new physical activities and new material-functional structures [START_REF] Fonte | Food consumption as social practice: Solidarity Purchasing Groups in Rome[END_REF][START_REF] Shove | Consumers, Producers and Practices: Understanding the invention and reinvention of Nordic walking[END_REF]. In this regard, the Challenge encourages the implementation of both cognitive processes and practical activities, which mostly imply collective problematisation and experimenting, but also offer conditions to integrate potential new habits. Moreover, the practical activities involving both volunteer citizens and public institutions representatives may offer a common ground where individual and institutional ambitions about sustainability can meet each other. With regards to previous studies about sustainable food consumption and programmes aiming at responsibilising the consumer, our results strongly encourage approaches looking at the consumer not only as guided by interests but as an individual joggling with several responsibility relations (individual, collective, systemic ones). In this view, empirical approaches may provide new perspectives about both the procedural and symmetric dimensions of food habits changes, which are fundamental to both explore institutional programmes and changes in food consumption. If previous studies demonstrate that some raising-awareness programmes about sustainability in food chains encourage greater reflexivity about systemic interdependencies [START_REF] Maye | Correction to: Ethics and responsibilisation in agrifood governance: the single-use plastics debate and strategies to introduce reusable coffee cups in UK retail chains[END_REF], we suggest that institutional experimental tools targeting consumers may enhance greater understandings of these systemic aspects if diverse agri-food system actors were involved.

Concluding Remarks

In response to climate and ecological challenges, this article argues that responsibility stakes in sustainable food consumption could be handled by observing both the transformation of consumption habits and the institutional tools aimed at responsibilising citizens. Indeed, a mismatching exists between how responsibility is constructed in food policies and how citizens view their responsibility towards themselves and their families. Moreover, these two visions mostly contribute to feed forms of responsibility based on self-interest, and hardly address collective needs or systemic perspectives on the food system. This survey explores an experimental tool implemented by local institutions that attempts to drive food consumption towards a greater awareness on health, economic and environmental issues. It shows that institutional experimental tools based on collective practical experience and combining both citizens and institutional representatives allow for reducing this gap thanks to practical and concrete exchanges among actors. If we accept that every habit transformation passes through disruption, problematisation and experimentation phases which involve meanings, competences and artefacts newly associated to these changes, these kinds of tools allow for facilitating both the cognitive processes and the conditions for adopting a new habit. Nevertheless, the major limitation of this study is that it doesn't consider long-term changes induced by this programme since it focused on collective moments and short-term changes in practice. Further research should therefore explore long-term effects of such institutional experimental tools and also compare them with food public policies based on more abstract and formal programmes.

  Mouans-Sartoux 2018/19 -21 households Cooking class (3)-purchase monitoring -purchase point tour (2) -nutrition workshop -farm visit -cooking class -food games evening -gardening workshop -no waste workshop -farm visit -food gathering workshop -budget workshop -purchase monitoring Loriol 2017 -14 households Purchase monitoring -gardening workshop -Cooking and nutrition workshop -Canning workshop -nutritional workshop -cooking class -food gathering of wild edible plantspurchase monitoring Valence 2019 -20 participants Cooking workshop -evaluation -visits to the producer's shop -exchange with a dietitian / gardening workshop Changes in Food Consumption Habits

Figure 1 .

 1 Figure 1. Habits transformation processes in life course and during the Challenge, the straight line indicates stages considered in the analysis.

The Food Challenge is openly inspired by the "Positive Energy Families Challenge," initiated in

with the aim of supporting families to save energy and water and reduce waste production; in the two case studies, it was preceded by a Positive Energy Family Challenge. Especially in one site, a fairly large number of families turned to Challenge following an experience with the energy Challenge. A certain familiarity with the format may have encouraged the participants to repeat the experience in a different and complementary domain. 2 https://www.famillesaalimentationpositive.fr/ ;

The Projets Alimentaires Territoriaux results from the Agriculture Law which encourages their development since 2014 and aim to relocate agriculture and food in the territories by supporting the installation of farmers, short circuits or local products in canteens;

They are generally grouped in teams of around 8/10 households;

A traditional dish of several south Mediterranean countries;

A nutritional mobile application; it enables food and cosmetic products to be scanned in order to obtain detailed information on a product's impact on health.

Centre Communal d'Action Sociale;

Acknowledgements

Authors are deeply grateful to the two anonymous reviewers for their relevant and insightful suggestions. The authors would like to thank to the Special Issue coordinators and especially Joost Dessein for his valuable and constructive remarks. This research was supported by the doctoral programme of ADEME, The French Agency for Ecological Transition. Mouans-Sartoux case study was found by Cin'In programme of the French Minister of Ecological Transition. The Drôme case study was supported by the Fondation de France. The authors sincerely acknowledge the Mouans-Sartoux municipality and the Urban Community of Drôme Valley for their valuable support in data gathering. Thanks also to Morgan Jenatton for Englishlanguage editing.