Finding alternatives to develop more sustainable food systems is a major challenge that society is facing today. Multiple efforts are being devoted to better understand such food systems, and consequently, to develop more sustainable alternatives (e.g., [1
]). In this context, food waste has emerged as one of the most relevant domains of the current unsustainability [5
]. The estimates of the Food and Agricultural Organization of the United Nations (FAO) suggest that one-third of the food produced globally is being lost or wasted along the food supply chain [6
]. In Europe, a recent estimation has indicated that 88 million tons of food are wasted annually [7
]. The magnitude of the numbers has fostered wide and growing agreement regarding the necessity of urgently addressing the issue of food waste generation. The United Nations agreed in 2015, within the definition of its Sustainable Development Goals, to halve food waste and reduce food losses by 2030 [8
]. In Europe, the European Union’s (EU) recently approved Circular Economy Package has allocated a key role to food waste prevention and reduction [9
The increasing awareness of the importance of the food waste challenge has grown in parallel with the number of publications devoted to better understanding this phenomenon, especially during the last decade [10
]. Such publications have been particularly focused on the consumption stage [11
]. The research on food waste has been diverse. To date, the relevant publications have mainly been focused on understanding consumer behavior (e.g., [12
]) or quantifying the generated volume of food waste (e.g., [16
]) and its associated environmental or economic impact (e.g., [16
]). However, there is still considerable room for advancement. Numerous gaps still prevail concerning the underlying factors of food waste generation [10
]. Despite efforts to standardize food waste quantifications (e.g., the Food Loss and Waste protocol [23
] and the Food Use for Social Innovation by Optimising Waste Prevention Strategies (FUSIONS) protocol [24
]), there is still no single agreed-upon definition of food waste, neither internationally nor in Europe [22
]. The discrepancies in the more adequate methodologies for undertaking the sound quantification of food waste make it difficult to compare results from different studies [10
]. The complexity of the phenomenon suggests the necessity of taking a step back and examining the roots of the food waste phenomenon.
Despite the rapidly increasing body of literature dealing with the food waste issue, only a few studies have attempted to focus on analyzing where the roots of the problem lie, that is, the causes of the phenomenon. A great diversity of studies, ad hoc reports, papers, and books have been published in the last decade (see Table 1
). They fundamentally employed secondary data to identify the causes of food waste at different geographical scales, ranging from worldwide to regional levels of analysis. Most of these studies used a partial view approach, that is, they included only specific stages of the supply chain in the analysis. On the other hand, those considering all the stages of the food supply chain dealt with secondary data. To our knowledge, there is only one study—by Göbel et al. [28
]—that has used primary data, which was collected by means of expert interviews along the whole food supply chain in the region of North Rhine-Westphalia in Germany to examine the causes of food waste using whole-supply-chain analysis.
As shown in Table 1
, the great majority of the existing works dealing with the causes of food waste partially examine the issue. Thus, there is a need to implement approaches better suited to capture the inherent complexity of the occurrence of food waste. In this context, there is also a growing concern among the leading organizations about the importance of implementing multidimensional and whole-supply-chain approaches to more adequately examine the food waste phenomenon [5
The geographical scope of the analysis is also relevant when addressing food waste. The scale determines the governance of all the agents implicated in the design of alternatives to the identified problems [57
]. Global recipes are often disseminated to address food waste at different levels: the international, European, country-specific, regional, or municipal level. Nevertheless, recent evidence has suggested that cultural and regional characteristics could be, to a certain extent, key determinants of food waste generation [58
]. In this context, the Resource Centres on Urban Agriculture and Food Security (RUAF) Foundation and FAO have advocated for the use of City Regions Food Systems as an appropriate approach that provides a valuable and useful scope for understanding food waste occurrence within a food system [5
]. Moreover, as a result of the Milan Urban Food Urban Pact, food waste has become one of the priority areas for the sustainability of cities [61
Thus, considering both the lack of multidimensional and whole-supply-chain approaches and the key role regions will have to play in the fight against food waste, here, we aimed to fill this void by conducting a holistic analysis of the causes of food waste in a particular region, the metropolitan region of Barcelona. The objective of this work was twofold: first, to identify the causes of food waste in the metropolitan region of Barcelona; and second, to examine the circumstantial or structural nature of the causes of the food waste. In doing so, we examined the perceptions of key stakeholders along the food supply chain in the metropolitan region of Barcelona through in-depth interviews. All the interviews were analyzed by content analysis, and the main causes identified by the regional stakeholders were classified according to a specific framework based upon the previous literature.
2. The Case Study: The Metropolitan Region of Barcelona
The metropolitan region of Barcelona is one of the most populated areas of Europe, located on the Mediterranean coast in the autonomous community of Catalonia, in Spain. It has a population of more than 4.8 million people in an area of 3236 km2
]. The agri-food sector is highly relevant in the metropolitan region through all stages of the food supply chain. A peri-urban agricultural park is located in the region, with more than 2800 producers (Baix Llobregat Agricultural Park). The land allocated to agricultural production is not very large, yet, the agricultural park has contributed to preserving the farming sector in the peri-urban environment [63
]. The industrial agri-food sector is the second most important economic sector in Catalonia. Multiple national and international food companies’ central headquarters are located in the region [64
]. The Barcelona central wholesale market is one of the main food clusters in southwestern Europe. Moreover, Barcelona city is known for its hospitality sector’s broad offerings and fresh food local markets. Regarding waste generation, the food industry is the major generator of tons of industrial waste, which represented 25% of the total industrial waste in Catalonia in 2013 [65
]. At the municipal level, 475 kg of waste per person per year was collected in 2013—bio-waste was the main contributor [66
During recent years, different initiatives to prevent and reduce food waste have been started in Spain. They are largely led by grassroots movements and NGOs (e.g., “Yo no desperdicio
] and “No tires la comida
]), but also by other different agents, such as public bodies (e.g., “Mas alimento menos desperdicio
] and “Som gent de profit
]) and private companies (e.g., “La alimentación no tiene desperdicio, aprovechala
]). However, it should be noted that, in Spain, the authority to regulate waste and food has been transferred to autonomous regions since the 1980s. Consequently, each autonomous region might show a different level of engagement in the food waste challenge. Catalonia concentrates most of its initiatives for food waste prevention and reduction in the metropolitan region in particular.
In spite of this growing interest, the scientific literature on food waste in Spain is scarce (e.g., recent publications [34
]). The dissemination of research results has been primarily conducted through outreach documents and reports. In any case, most of the studies have been focused on one single stage of the food supply chain—whether primary production [42
], the food industry [44
], the supplier–retailer interface [34
], food distribution and food service [43
], or the consumption stage [35
]. In Catalonia, a specific quantification of food waste from distribution to households was carried out in 2010 [36
]. Additionally, most of the studies have used different food waste conceptual frameworks and scopes, if any, which makes it difficult to make comparisons between them or even with other studies abroad. In the metropolitan region of Barcelona, there has been no specific study on food waste, apart from studies addressed to better understand consumers’ behavior in relation to food waste [74
3. Conceptual Framework to Distinguish Structural and Circumstantial Causes
According to the High Level Panel of Experts (HLPE) on Food Security and Nutrition [22
], the causes of food waste are complex and can be classified into three levels—micro, meso, and macro—according to their complexity and relationship with other drivers, as follows:
Micro causes: specific causes of food waste occurring at each stage of the food supply chain due to the actions or inactions of agents at the same stage. They are not necessarily linked to other causes. Micro causes are not influenced by the behavior of agents at other stages.
Meso causes: secondary or structural causes that can be found in another stage. They occur because of the interaction between agents or because of the existing infrastructures where food is produced, distributed, sold, and so forth.
Macro causes: those rooted in the food system dynamics as a whole. These are systemic issues affecting the two previous levels (micro and meso), such as the policy conditions in terms of regulation or the functioning of the food system; that is, “macro causes favor the emergence of all the other causes of food loss and waste” [22
Distinguishing between these three groups of causes is useful to evaluate the magnitude and the nature of the problem posed by food waste in each case. This classification helps to differentiate between the circumstantial nature of the causes of food waste, aligned with the micro causes, and the structural nature of the causes of food waste, aligned with the meso and macro causes.
Alternative literature has suggested other classifications as well, to disentangle the true nature of the different causes. In this study, we will use such classifications to better describe the identified causes. Thus, the causes of food waste within each level (micro, meso, and macro) can be subdivided into four additional categories: (1) technological causes [50
], which are related to technical inefficiencies or failures at different stages of the food supply chain; (2) economic and business management causes [28
], linked to the business strategies of the different actors along the food chain: contract standards, operational actions, and the commercial relationships of the stakeholders in the food chain; (3) regulatory and policy causes [28
], which are rooted in norms and regulations that affect the food sector, such as urban waste or food regulations, which may affect food waste generation; and (4) appreciation and enhancement causes [28
] (also known as values, information, and skills in other studies), which are related to awareness, information, or specific habits. This classification helps to identify the domains where food waste occurs and to anticipate the skills (profiles) and contexts that would be required to solve such drivers. These four domains were proposed by Canali et al. [50
] based on consultations with experts and an extensive literature review. Moreover, a similar classification is used in other publications such as Göbel et al. [28
] or Thyberg and Tonjes [49
]. Finally, the specific stages of the food supply chain where the identified causes apply are also relevant for analyzing the food waste conundrum.
To achieve more sustainable food systems, it is crucial to better understand all the negative externalities affecting such systems. Food waste is one of the key components of the current unsustainability of food systems and further attention should be devoted to it. Despite the generalized interest in preventing and reducing the current volumes of food waste, we believe that the partial approaches employed to study the situation so far have possibly blurred global comprehension of the nature of the problem. This paper has aimed to contribute to fill this gap by undertaking a participatory, holistic, and whole supply chain analysis of the causes of food waste generation in the metropolitan region of Barcelona. We have carried out a qualitative assessment of the perception and the causes of food waste. An extensive map of the causes of food waste in the region is provided by structuring these, according to their level (micro, meso, macro) and their nature (technological, economic and business management, regulatory and policy, and appreciation and enhancement). By comparing our findings with previous literature, we identified common and specific causes of food waste.
We fulfilled the two main objectives of the paper. First, the relevant stakeholders’ perceptions and the causes of food waste in the metropolitan region were identified and detailed. The stakeholders in this study showed a great interest in food waste prevention. The social dimension of the problem (the difficulties of access to food faced by some segments of the population) is a key factor for the stakeholders. Therefore, food redistribution was a key issue during interviews. Moreover, the farming level was focused upon substantially, despite the fact that the metropolitan region is not a high-food-producing region. We have provided a detailed map of the causes of food waste at different stages in the region. However, it should be noted that this is a qualitative study that was focused on obtaining a wide picture of food waste drivers by considering a heterogeneous panel of key stakeholders. Further research on the impact and the importance of each identified cause on the current food waste volume should be conducted. Despite that fact, the set of the causes identified should be useful to policy bodies and agri-food operators in the region to work towards food waste prevention and reduction. Each agent can better identify the domain they could have more influence on.
Secondly, this paper has differentiated between the circumstantial and structural causes of food waste. The approach used in this study has allowed us to identify the complexity of the food waste conundrum. Food waste drivers are spread throughout different stages of the food supply chain, at different levels—micro, meso, and macro. We employed this distinction, in line with the HLPE [22
], to disentangle the circumstantial or structural nature of food waste generation. We believe that the ways to approach and solve these two causes should be radically different. Incidental or circumstantial causes can be addressed with stage-focused approaches. However, structural causes require holistic approaches. Moreover, we classified each cause according to its nature (technological, economic and business management, regulatory and policy, and appreciation and enhancement) which is useful for both further research and policymakers to identify the domains to focus on, according to their skills and/or domains of action. Additionally, alternative classification of causes can be conducted, the two approaches used here were useful to understand the food waste phenomenon in the region. We recommend that future studies use them to disentangle the complexity of food waste.
The results from this study indicate that food waste is a structural problem, which is mainly linked to the current structure of the food supply chain and not to particular and isolated inefficiencies. Nevertheless, micro causes were also identified in relation to the existing inefficiencies of specific processes at specific stages of the food supply chain. Hence, partial and focused measures and approaches would be enough to solve theses. We encourage agri-food operators and policymakers to address them. However, they should not forget the structural nature of the food waste problem. We found that the meso and macro causes mentioned by the stakeholders were mainly related to the food system dynamics and the existing interrelationships among the stakeholders in the food supply chain. They cannot be understood with partial views, and whole-supply-chain measures are needed. Overall, our results are in line with the partial results found in the literature. However, this study provides a more global perspective. This holistic approach should be followed in future research in order to corroborate our results in other geographical contexts.
Food waste is a complex issue affecting a large number of agents. Although food waste awareness has significantly increased during the last decade, the literature review undertaken in this study indicated a lack of studies on food waste causes that utilize whole-supply-chain approaches. It is true that in the area of consumer behavior, there is increasing research focused on understanding consumers’ behavior and perceptions. However, consumers do not hold the ultimate responsibility for food waste. Our research contributes to the literature by providing a regional stakeholders’ perspective about food waste along the food supply chain.
Finally, this study shows that a regional scope is an adequate scale by which to analyze the problem of food waste. We found specifications from the region that would not have been identified with a broader geographical scope (e.g., national, European, worldwide). Most of the studies on food waste published in peer-reviewed journals are located in the United States or the United Kingdom. Replicating more regional studies would contribute to the international debate, and we would be able to identify alternative policies more suited to the relevant territories and cultures.
Despite all the cautions that should be considered in interpreting the results of this study, we consider that this paper offers an innovative approach to analyze the food waste problem. Moreover, the findings could be of interest to both researchers and policymakers from the studied region and further afield.