Systematic Literature Review on Sustainable Consumption from the Perspective of Companies, People and Public Policies

: Sustainable consumption requires that people, companies, and nations promote correct use of their resources in the interest of environmental protection and ecosystem integrity. Given the relevance of this subject, the main objective of the present study was to provide an overview of the literature on sustainable consumption, going beyond knowledge related to consumer behavior, and addressing questions connected with the role of companies and public policies in the promotion of sustainable consumption. To achieve that, a systematic literature review was carried out by selecting 114 articles published over the past ten years, from Web of Science categories with an environmental focus. The study allowed for showing the state of the art of the subject, as well as suggestions for future studies based on gaps in the literature. It was found that there is a concentration of studies oriented toward surveying and understanding consumer behavior at the expense of those focused on examining companies and their relationship with sustainability and consumption.


Introduction
Observation of changes that have been occurring in social contexts suggests an increasingly marked need to restructure organizational practices in companies to guarantee their continuity [1]. Implementation of sustainable processes has received more attention in research, since structural and behavioral changes in companies are driven less by competition and more by the need for organizational legitimacy [2].
Sustainable consumption, in its essence, is a normative concept that requires people, companies, and nations to reduce the "footprints" they leave by incorrect use of resources in the interest of environmental protection and ecological integrity [3]. This type of consumption involves many factors beyond individual behavior, given that cultural, social, historical, and economic factors can influence consumption decisions [4]. This is a subject of extreme relevance for minimizing the impacts on the environment caused by inadequate (sometimes irresponsible) consumption, which motivates the development of studies that point to difficulties and barriers to sustainable consumption, and guidelines, opportunities, and innovations that can be used to overcome these barriers. These topics are aligned with what is considered essential for companies and consumers to expand their knowledge or guide their first steps toward practices that favor sustainable consumption. In this context, in an attempt to increase knowledge about the subject, the present study had as a general objective to carry out a systematic literature review on sustainable consumption, with a main focus on the business environment of companies, but without neglecting to address issues related to consumer behavior and public policies.  [17] and Tranfield et al. [10].
The process of carrying out a systematic literature review begins with planning, which involves a definition of the study scope [19] and objective [10], protocol formulation, and team training [17]. Subsequently, during selection, the data search strategy is defined [10,12,19] and a bibliographic survey is carried out [17]. The extraction phase involves obtaining and evaluating the research material [10,12,19]. The last step, execution, focuses on study synthesis and writing [17].
According to Tseng et al. [18], systematic literature reviews have four steps, which involve, in short, data identification, initial data screening, eligibility determination, and data inclusion. The steps represented in Figure 1 (construed as macroprocesses) can be split up into smaller steps (microprocesses), as indicated by Soni and Kodali [20] and Hall et al. [14] and shown in Figure 2 by Okoli [17].
During the selection phase, the data search strategy, specifically regarding keywords, must be chosen carefully, because if the choice is poor, additional efforts will be required of researchers in the initial data screening step [12].

Systematic Literature Review
In this section, the produced systematic literature review is presented. The section is in seven parts: (i) definitions of sustainable consumption; (ii) historical evolution of sustainable consumption; (iii) sustainable consumption from the perspective of materials and methods used; (iv) contributions of sustainable consumption to companies; (v) barriers to the adoption of sustainable consumption by companies; (vi) guidelines for the adoption of sustainable consumption by companies; and (vii) sustainable consumption-related innovations.

Definitions of Sustainable Consumption
The formal introduction of the "sustainable consumption" concept occurred during the United Nations Conference on Environment and Development in 1992, in Rio de Janeiro, Brazil. The definitions of sustainable consumption address the environmental consequences of consumption acts [26]. Several authors stated that sustainable consumption is a great source of concern for society and business [27].
Barber [28] stated that sustainable consumption raises awareness and brings about changes in the values and motivations that lead to consumer behavior. The concept emerged as a response to sustainability challenges faced by communities around the world [29]. Sustainable consumption involves sustainable solutions seen as crucial for changing production and consumption patterns [30].
From the organizational point of view, the concept is related to sustainability and green technologies, which are used in attempts to bring benefits to companies, such as improvement of their image or even economic advantages [31]. One of the concepts used that is aligned with sustainable consumption is sustainable consumption and production (SCP), defined by the United Nations Sustainable Development Goals as promoting resources and energy efficiency, sustainable infrastructure, access to basic services and green and decent jobs, and a better quality of life for all [32].
It is common to find articles that address both sustainable consumption and SCP in the literature, since discussions of these subjects complement each other. However, studies more focused on SCP have involved more organizational or political contexts, such as those that have addressed the sharing economy [29,32,33], measures for adoption of sustainable processes [34], and future challenges related to sustainability in countries [30].

Historical Evolution of Sustainable Consumption
According to Yarimoglu and Binboga [35], a tendency toward social change in consumer behavior in developed countries already existed, showing that they voluntarily began worrying more about sustainability and "green" products. This social change prompted the development of many studies in different spheres and from different perspectives on sustainable consumption. The diversity in the "sustainability consumption" subject allowed the field of study to expand into areas that examine people's social behavior and its impacts on the public sector by analyzing regional and national public policies, and on the private sector by considering the realities of companies and their relationships with their target audiences.
The articles used in the present literature review were separated and organized into research areas to facilitate the understanding of the extracted results. The most active areas of research over the past ten years were: "people's sustainable behavior", "public policies and countries", and "companies and business environments". These divisions and their branches are shown in Figure 4. The thematic area "people's sustainable behavior" was created to group articles that discussed sustainable consumption by focusing specifically on the daily behavior of study populations, taking into account cultural, economic, educational, and social aspects. This area was split into "social and economic factors", "personal factors", and "role of education in consumption". "Public policies and countries" is a thematic area that included publications that addressed sustainable consumption as public policies or reported good sustainable consumption practices either in urban environments or as national policies. This area was divided into "legal and normative incentives", "public policies in cities", and "national public policies".
Lastly, the division "companies and business environments" put together the studies on sustainable consumption in business settings, more specifically surveys of company structures, commitment to SCP in production processes, and stakeholder behavior. The area was split into "infrastructure and organizational environment", "sustainable consumption and production", and "consumer and stakeholder behavior".
To facilitate further analysis of the articles and follow the evolution of the subject over time, Figure 5 shows the publications by thematic areas and their branches by year of publication of the studies. The thematic area "people's sustainable behavior" was created to group articles that discussed sustainable consumption by focusing specifically on the daily behavior of study populations, taking into account cultural, economic, educational, and social aspects. This area was split into "social and economic factors", "personal factors", and "role of education in consumption". "Public policies and countries" is a thematic area that included publications that addressed sustainable consumption as public policies or reported good sustainable consumption practices either in urban environments or as national policies. This area was divided into "legal and normative incentives", "public policies in cities", and "national public policies".
Lastly, the division "companies and business environments" put together the studies on sustainable consumption in business settings, more specifically surveys of company structures, commitment to SCP in production processes, and stakeholder behavior. The area was split into "infrastructure and organizational environment", "sustainable consumption and production", and "consumer and stakeholder behavior".
To facilitate further analysis of the articles and follow the evolution of the subject over time, Figure 5 shows the publications by thematic areas and their branches by year of publication of the studies.
When the decade began in 2011, the studies had the objective of helping to elucidate the role in sustainable consumption played by two factors. One was that of governments, by means of the creation of incentive policies [36] or the establishment of rules for the development of products [37]. The other was the internal aspects of companies, including alterations in their structure and policies to be implemented to encourage adherence to sustainable consumption [38].  When the decade began in 2011, the studies had the objective of helping to elucidate the role in sustainable consumption played by two factors. One was that of governments, by means of the creation of incentive policies [36] or the establishment of rules for the development of products [37]. The other was the internal aspects of companies, including alterations in their structure and policies to be implemented to encourage adherence to sustainable consumption [38].
This trend persisted until 2013, when the focus of the studies was reoriented toward greater concern with surveying and understanding perceptions, motivations, and values of consumers that were or were not associated with sustainable consumption practices [39][40][41][42]. This trend persisted until 2013, when the focus of the studies was reoriented toward greater concern with surveying and understanding perceptions, motivations, and values of consumers that were or were not associated with sustainable consumption practices [39][40][41][42].
Over the past five years, there has been a gradual increase in the number of studies on education and sustainable consumption, since schools and universities can be foundational for ideas and attitudes of populations [43][44][45].  Figure 6 shows the grouping of methods found in the articles selected for the present systematic literature review.

Sustainable Consumption from the Perspective of Used Materials and Methods
Over the past five years, there has been a gradual increase in the number of studies on education and sustainable consumption, since schools and universities can be foundational for ideas and attitudes of populations [43][44][45] Figure 6 shows the grouping of methods found in the articles selected for the present systematic literature review. Examination of the 114 publications selected for the present review showed that there were 61 publications with objectives oriented toward elucidating what influenced people's behavior in a certain context or analyzing a specific reality in more detail. To achieve that, primary (such as interviews, questionnaires, and case studies) and secondary (surveying data in books, documents, etc.) data collection methods were the most used.

Sustainable Consumption from the Perspective of Used Materials and Methods
Interviews and questionnaires were the techniques chosen in studies that concentrated their efforts on understanding people's behavior (57 publications). In these studies, direct questions about perceptions regarding sustainable consumption, reasons why or why not it was practiced, and other issues were asked of the examined public [46]. This type of study can formulate hypotheses on the subject being addressed that are directly connected with the established research problems, so questions to be asked can be drafted and the hypotheses confirmed or not. The study by [47] proposed eight hypotheses about the relationship between marketing strategies, consumer frugality, and consumer behavior. Analysis of 387 users of websites and social media in China proved all hypotheses correct and allowed conclusions that e-mavenism (that is, distribution of information on the internet and searches of consumers) was positively correlated with frugality, which, in turn, was essential for people to adhere to sustainable consumption.
These techniques can be applied together with the case study method. Da Silva et al. [1] used information obtained from a Brazilian company in an attempt to identify the role played by stakeholders in incentives for sustainable consumption in the electricity sector. Figure 7 shows the number of studies published over the period covered in the present systematic literature review and compares the main research methods used. Examination of the 114 publications selected for the present review showed that there were 61 publications with objectives oriented toward elucidating what influenced people's behavior in a certain context or analyzing a specific reality in more detail. To achieve that, primary (such as interviews, questionnaires, and case studies) and secondary (surveying data in books, documents, etc.) data collection methods were the most used.
Interviews and questionnaires were the techniques chosen in studies that concentrated their efforts on understanding people's behavior (57 publications). In these studies, direct questions about perceptions regarding sustainable consumption, reasons why or why not it was practiced, and other issues were asked of the examined public [46]. This type of study can formulate hypotheses on the subject being addressed that are directly connected with the established research problems, so questions to be asked can be drafted and the hypotheses confirmed or not. The study by [47] proposed eight hypotheses about the relationship between marketing strategies, consumer frugality, and consumer behavior. Analysis of 387 users of websites and social media in China proved all hypotheses correct and allowed conclusions that e-mavenism (that is, distribution of information on the internet and searches of consumers) was positively correlated with frugality, which, in turn, was essential for people to adhere to sustainable consumption.
These techniques can be applied together with the case study method. Da Silva et al. [1] used information obtained from a Brazilian company in an attempt to identify the role played by stakeholders in incentives for sustainable consumption in the electricity sector. Figure 7 shows the number of studies published over the period covered in the present systematic literature review and compares the main research methods used.
Surveying documents and applying questionnaires and interviews can be used in tandem, such as in the process of gathering information on a company and its stakeholders to identify what roles these people play in incentives for sustainable consumption, specifically in the electricity sector [1].
Theoretical studies were the second most common type. Many publications reported creation or application of these theories to try to understand decisions made by consumers, consciously or unconsciously [48]. The present systematic literature review could fit into this group, because it adds a more recent view to previous studies and sought to organize information that could be useful for improving future studies on sustainable consumption. In this theoretical field, there were 11 articles addressing people's sustainable behavior, 3 publications about public policies and countries, and 8 articles discussing the topic of companies and business environments.  Surveying documents and applying questionnaires and interviews can be used in tandem, such as in the process of gathering information on a company and its stakeholders to identify what roles these people play in incentives for sustainable consumption, specifically in the electricity sector [1].
Theoretical studies were the second most common type. Many publications reported creation or application of these theories to try to understand decisions made by consumers, consciously or unconsciously [48]. The present systematic literature review could fit into this group, because it adds a more recent view to previous studies and sought to organize information that could be useful for improving future studies on sustainable consumption. In this theoretical field, there were 11 articles addressing people's sustainable behavior, 3 publications about public policies and countries, and 8 articles discussing the topic of companies and business environments.
Application of diverse methods was also found, although in smaller number. Some examples that stood out were the use of an analytical hierarchy process to prioritize barriers dealt with in the adoption of sustainable consumption by production chains [49] and studies focused on creating a business model that encouraged sustainable consumption in companies in a circular economy [50].

Contributions of Sustainable Consumption to Companies
Sustainable consumption of resources used in the production process by companies has the objectives of offering ecologically correct products, adjusting production activities to socioenvironmental realities, and promoting good practices by the consuming public. Given increased concern shown by populations about sustainability, companies that adopt sustainable consumption or measures that encourage it end up creating positive perceptions in the public, who become more likely to buy their products or services [51]. Application of diverse methods was also found, although in smaller number. Some examples that stood out were the use of an analytical hierarchy process to prioritize barriers dealt with in the adoption of sustainable consumption by production chains [49] and studies focused on creating a business model that encouraged sustainable consumption in companies in a circular economy [50].

Contributions of Sustainable Consumption to Companies
Sustainable consumption of resources used in the production process by companies has the objectives of offering ecologically correct products, adjusting production activities to socioenvironmental realities, and promoting good practices by the consuming public. Given increased concern shown by populations about sustainability, companies that adopt sustainable consumption or measures that encourage it end up creating positive perceptions in the public, who become more likely to buy their products or services [51].
One study pointed out that production systems that respect sustainable consumption limitations, in addition to strengthening the image of companies, end up positively influencing the economic performance of organizations [52]. It was also found that each market required its own SCP policies, depending on the economic growth level [53].
The literature indicated the need for critical changes in sustainable business analysis, which include considering sociocultural dimensions to reinforce brand socialization and climatic care. This could contribute to more progressive social action on climate change [54]. However, adopting sustainable consumption may not be so simple for some companies. For multinationals, this could imply seeking to understand sustainability incentive policies, or prohibition of parts of their production systems in certain countries, and consideration of how to adapt to these rules [30]. For companies in general, this may result in replacement of systems and infrastructure with more sustainable, and even more technological, processes [55].
International companies need to assess the motivations of consumers that cause them to engage in sustainable consumption in the countries where these organizations develop their activities [56]. They can also adopt smart grids. Since new technologies expand consumer scope, they create new sustainable consumption opportunities [57]. Because companies face difficulties when they formulate plans that incorporate sustainability into their activities, Table 1 shows the contributions by several authors in different contexts to help guide companies that seek to gain deeper knowledge of the subject. Table 1. Studies that offered contributions to companies regarding sustainable consumption.

Contributions to Companies Author(s)
Suggested that governance models (environmental laws) can promote the mode of operation of industrial symbiosis. Lehtoranta et al. [37] Identified the need for mutual and complementary interaction between stakeholders. Da Silva et al. [1] Proposed the "meta labeling" system to make it easier for consumers to align their purchase decisions with sustainable development goals. Dendler [58] Contributed to the discussion about approaches to systemic thinking from the sustainable consumption perspective. Sedlacko et al. [59] Argued that SCP must be discussed by means of a political agenda. Akenji and Bengtsson [60] Explained how material values and social recognition influence sustainable consumption in the transcultural context. Ceglia et al. [4] Demonstrated the efficacy of descriptive rules when they influence pro-environmental behavior in the online shopping context. Demarque et al. [61] Showed the participation of Portuguese public transport companies in management and sustainability practices. Cruz and Katz-Gerro [31] Provided an evaluation instrument that assigned a score for the level of sustainability of companies (more specifically, for the products they offered) with the objective of decreasing information asymmetry between buyers and sellers.
Nikolaou and Kazantzidis [62] Demonstrated the role played by managers when they deal with institutional pressures during SCP implementation, based on institutional theory and agency theory. Dubey et al. [2] Presented a structural model to analyze barriers to acceptance of insertion of SCP strategies in the supply chain. Mangla et al. [49] Explored the use of value propositions that shape sustainable consumption by means of examples of product-service systems. Stal and Jansson [63] Consolidated the mode of consumption and production based on the upgrade capacity of product-service systems (upgradable product-service systems). Pialot et al. [64] Showed consumers' acceptance of product-service systems.
Catulli et al. [55] Contributed to a structure focused on adoption of SCP to help regulatory agencies, managers, consumers, and policymakers. Luthra et al. [34] Sought to elucidate the intricate relationships between sustainability, operations, and marketing by discussing customization of sustainable products and how these products can generate demand as a result of personalization and durability.
Ulku and Hsuan [65] Listed the main barriers identified in each dimension (internal and external) faced by companies. Torkabadi et al. [66] Suggested that business models allow for achieving sustainable consumption. Tunn et al. [50] Contributed to the perception that companies that achieve better environmental performance are more likely to disseminate environmental information. Nishitani and Kokubu [52] Sought to elucidate how purchase and use of sustainable services can replace unsustainable alternatives. Soler et al. [67] Suggested that each market requires their own SCP policies, depending on the economic growth level. Yagi and Kokubu [53]

Contributions to Companies Author(s)
Sought to explain the factors that contribute to sustainable consumption in specific segments of the market and help companies incorporate sustainability into their activities to improve their image and reduce their impact.
Quoquab & Mohammad [68] Suggested that international companies need to assess the motivations of consumers that cause them to engage in sustainable consumption in the countries where these corporations develop their activities and evaluate the absolute impacts of the sustainability of their initiatives.
Iran and Müller [56] Pointed out that companies can adopt smart grids, since new technologies expand consumer scope, leading to new sustainable consumption opportunities. Schappert and von Hauff [57] 3. 5

. Barriers to Adoption of Sustainable Consumption by Companies
Although sustainable consumption has been shown to have a growing trend over the years, it has not always translated into action, because of the existence of several barriers. Therefore, managers must be aware of these obstacles so organizations can plan ways to "take the first steps" toward sustainable consumption. According to Torkabadi et al. [66], internal barriers (such as economic conditions, knowledge or technological limitations, incompetence of the workforce, and lack of support by management) have a greater impact than external barriers (for instance, legislation and consumer behavior). Table 2 shows the most relevant barriers found in each research area in the selected articles. Existence of few studies to understand the practice Stål and Jansson [63] From the consumer point of view, lack of knowledge and resistance to changing habits were the keys to failure or success in the creation of sustainable consumption projects [69]. Consequently, education plays a role in disseminating information about the benefits, either global or personal, of adopting sustainable practices [72][73][74].
Because consumption is a social phenomenon, several factors can influence the behavior of the population [90]. The notion of living in a state of "well-being" can be understood in dif-ferent ways, depending on geographic location [78], and what is expected from consumption practices can vary, too. In certain groups in more developed countries, for instance, people are expected to buy organic products or purchase most of their items of clothing in thrift shops, which creates a form of social pressure toward this type of consumption [76].
Additionally, it is difficult to measure consumers' emotions, but these feelings can also impact consumption decisions [77]. Usually, sustainable actions are translated into slogans such as "stop buying certain products" that result in behavioral changes. This effect can lead to negative feelings and resistance in consumers [75]. In the current context, social media affects consumer behavior and awareness of sustainable consumption positively and negatively, but they tend to create homogenized consumption, which, in many cases, exhausts the environment [71]. Therefore, efforts are necessary to promote sustainable consumption as something positive that can lead to global or individual benefits [79].
Pro-environmental behavior experts who face barriers to disseminating sustainable consumption resulting from pressure by industries can be considered highly conscious, motivated, and well-informed references, and they can critically impact other people and their consumption behavior [70].
Regarding the public policies and countries area, it is possible to state that lack of inspection and lack of incentives by regulatory institutions ends up influencing nonuse of sustainable production measures [81,82,91]. These types of incentives are more commonly found in developed countries, which causes this discussion to be overlooked in developing countries [35,80].
From the companies' perspective, the most evident barrier is financial, given that adopting sustainable measures can generate high costs to effectively adjust the organizational structure [67]. Additionally, these changes must be very well-disseminated over entire companies since these measures imply not only bringing new technologies to corporations but also affecting corporate governance as a whole [86]. Organizational changes must concomitantly involve managers, employees, stakeholders, and stockholders [84,85].
It is important to emphasize that companies are not isolated in the environment and that all previously cited barriers related to policies and consumers also impact organizations. Incentives to sustainable consumption must be a collective effort, and society as a whole must have them as a common objective. Otherwise, there will always be barriers to the adoption of this consumption system [87][88][89].
Lastly, the gap itself in the literature about incorporation of measures oriented toward encouraging sustainable consumption can be considered a barrier, because research on this subject is focused mainly on consumer purchasing behaviors. There are few studies on how companies try to shape sustainable consumption in practice, for instance [63].

Guidelines for Adoption of Sustainable Consumption by Companies
In addition to barriers, the examined literature also pointed out some guidelines and good practices that can be adopted to guarantee implementation of sustainable consumption practices in companies and society (Figure 8).
According to Lim, Arita, and Joung [92], consumers already understand what sustainable consumption is and, therefore, nonexistence of sustainability-related practices cannot be explained by knowledge deficits. The results reported in the selected studies suggested the need for positive and constant recognition by society, which leads to the practice of sustainability by the population, since individuals may not perceive themselves as part of society's decision-making [93] and may not identify the impacts of consumption on the environment. on this subject is focused mainly on consumer purchasing behaviors. There are few studies on how companies try to shape sustainable consumption in practice, for instance [63].

Guidelines for Adoption of Sustainable Consumption by Companies
In addition to barriers, the examined literature also pointed out some guidelines and good practices that can be adopted to guarantee implementation of sustainable consumption practices in companies and society (Figure 8). According to Lim, Arita, and Joung [92], consumers already understand what sustainable consumption is and, therefore, nonexistence of sustainability-related practices cannot be explained by knowledge deficits. The results reported in the selected studies suggested the need for positive and constant recognition by society, which leads to the practice of sustainability by the population, since individuals may not perceive themselves as part of society's decision-making [93] and may not identify the impacts of consumption on the environment.
A study by Lo [94] examined sustainable consumption practices in metropolitan regions by consulting the Organisation for Economic Co-operation and Development database. The study showed that these practices were associated with socioeconomic factors, and that there was not a direct association with urban structure. Efforts to boost a transformation toward urban sustainability, especially regarding lifestyle and behaviors, mean more than developing adequate infrastructures. They also require innovation in governance and institutional alterations, that is, changes in norms, formal and informal rules, laws, cognitive structures, policies, and governance systems that shape the way people see the world and think about it [95].
Another important step toward adoption of sustainable consumption by companies is a greater understanding of consumption practices by society as a whole, since this would be necessary to change people's routines and concepts about sustainable options in order to get more visibility, which could lead to modifications in people's behavior and the contexts in which actions occur [31]. Consequently, it is fundamental to develop new studies and theories about consumer behavior. One possibility is designing general or specific studies funded by certain organizations to elucidate their consumers' preferences, sustainability-related concerns, and what their public expects of and accepts in offered products and services [4].
From a more internal perspective, organizations also have their own consumption behaviors when buying supplies to produce their goods or services. Measures to achieve the adoption of sustainable consumption may require that many processes be altered [52] and that investments in new technologies be made [96]. Understanding internal processes and which changes must be carried out is important, in order for these actions to be seen A study by Lo [94] examined sustainable consumption practices in metropolitan regions by consulting the Organisation for Economic Co-operation and Development database. The study showed that these practices were associated with socioeconomic factors, and that there was not a direct association with urban structure. Efforts to boost a transformation toward urban sustainability, especially regarding lifestyle and behaviors, mean more than developing adequate infrastructures. They also require innovation in governance and institutional alterations, that is, changes in norms, formal and informal rules, laws, cognitive structures, policies, and governance systems that shape the way people see the world and think about it [95].
Another important step toward adoption of sustainable consumption by companies is a greater understanding of consumption practices by society as a whole, since this would be necessary to change people's routines and concepts about sustainable options in order to get more visibility, which could lead to modifications in people's behavior and the contexts in which actions occur [31]. Consequently, it is fundamental to develop new studies and theories about consumer behavior. One possibility is designing general or specific studies funded by certain organizations to elucidate their consumers' preferences, sustainability-related concerns, and what their public expects of and accepts in offered products and services [4].
From a more internal perspective, organizations also have their own consumption behaviors when buying supplies to produce their goods or services. Measures to achieve the adoption of sustainable consumption may require that many processes be altered [52] and that investments in new technologies be made [96]. Understanding internal processes and which changes must be carried out is important, in order for these actions to be seen as positive by the entire organization, so other stakeholders can be mobilized, too, including the media and third-sector companies [1].
The guidelines based on the results mentioned by the authors cited in this subsection reinforce the need for coordinated strategies between several sectors that allow not just understanding what sustainable consumption practice really is but also creating incentives that encourage the participation of society, together with companies and public institutions. There is not a direct relationship between the level of urban development and sustainable practices. However, it was shown that studies that delved more deeply into everyday behavior found that people in areas with higher levels of urban development were more prone to engage in pro-environmental behavior. Therefore, it is crucial to develop public and private policies without ignoring the individual initiatives of certain groups, in order for society to deal more naturally with sustainable consumption in everyday life. Lim, Arita, and Joung [92] stressed that the lack of such naturalness was associated with the population's not being used to certain habits. Consequently, incentives by companies and authorities are fundamental for changing habits. Table 3 summarizes new ideas, theories, and methods applied in studies that addressed sustainable consumption.

Research Area Authors Presented Innovation
People's sustainable behavior (Social and economic factors) Caeiro et al. [97] Developing an approach to defining the main steps and criteria for formulation and evaluation of "sustainable household consumption" by means of sets of indicators.
Di Giulio and Fuchs [98] Determining how realistic the approach "sustainable consumption corridors" would be to increase the feasibility of sustainable consumption, both empirically and politically.
Companies and business environments (Infrastructure and organizational environments) Dubey et al. [99] Offering predictive analysis of collaborative performance metrics of companies that have practices related to sustainable consumption.
Biswas and Roy [96] Catulli, Cook, and Potter [55] Addressing use of new technologies for creation of new metrics, methods of production, and ways to disseminate information on sustainable consumption.
Public policies and countries (national public policies) Lukman, Glavič, Carpenter, and Virtič [30] Reporting positive results about sustainable consumption in developing countries.

Byers and Gilmer [69]
Creating a conceptual structure to address systematic, structural, and institutional perspectives on how consumption, by means of public policy initiatives, can be developed to reflect a deeper ecological basis.
Pineiro-Villaverde and García-Álvarez [100] Listing proposals oriented toward actions directly related to SCP, such as promoting use of recycled raw material in public works or requiring Ecolabel certification for agreements with public administrations.
Public policies and countries (legal and normative incentives) Wang et al. [101] Pioneering in the explanation of roles, behaviors, and strategies related to sustainable consumption in a sharing economy context. Guido et al. [102] Developing a food labeling index to promote sustainable consumption. The index is calculated by classifying several resources in the environmental, health, and nutritional dimensions of target products in relation to a reference value.
Some studies related to consumer sustainable behavior have developed evaluations to better elucidate the main steps and criteria involved in consumer behavior choices. Caeiro et al. [97] analyzed and quantified sustainable household consumption. Di Giulio and Fuchs [98] examined the concept of sustainable consumption corridors, which, by defining what the minimum and maximum standards for what people believe they need to have a "good life", can become an adequate starting point for establishing sustainable consumption criteria.
By considering companies' internal perspectives, it is possible to stress that building partnerships between organizations is currently perceived as a growth and development opportunity for them, because there can be exchanges of processes and good practices to increase their efficiency. These partnerships may also involve the establishment of sustainable consumption goals, as shown in a study by Dubey et al. [99], which measured collaborative performance in consumption goals, and even sustainable production of associate companies, by means of big data and predictive analysis.
Examination of technological innovations that are being developed and widely disseminated in society and organizations allows the identification of studies on the use of technology to spread information on the importance of sustainable consumption [96], creation of new production systems that implement sustainability measures [55], and data that include a description of characteristics related to environmental, health, and nutritional dimensions of target products in relation to reference values [102]. Information and knowledge provided in ecological labels, for instance, help with strategies to obtain energy efficiency in electronic devices [103].
In studies addressing public policies and countries, it was possible to notice progress in concerns of developing countries about sustainable consumption, a situation that can be considered newer, since, until recently, most studies on this subject focused on the realities of developed countries [30,35]. A tendency to expand proposals to carry out actions directly related to SCP was also identified [100]. Regarding the theoretical area, there have been innovations in considering systematic, structural, and institutional perspectives to foster understanding of how consumption [69] and sustainable consumption occur in other contexts, such as the sharing economy [101].
Finally, it is important to emphasize that consumption, whether sustainable or not, is a social phenomenon and, therefore, any changes experienced by societies can influence consumer practices [104], including economic changes, greater ecological concerns [105], and modifications of social values [106,107]. Consequently, there will always be innovations in the sustainable consumption research area.

Agenda and Directions for Future Studies on Sustainable Consumption
The challenges to bridging the gaps found in the selected studies also provide opportunities to obtain new results from different perspectives and contribute to the progress of studies on sustainable consumption in society. Table 4 puts together some subjects that required more studies and were addressed by some authors over the past decade. This list is not an exhaustive list. Table 4. List of recommended research subjects studied over the past decade.

Topics Recommended as Research Opportunities Researcher(s) That Followed These Recommendations
Business dynamics Sedlacko et al. [59], Doyle, Farrell, and Goodman [54], Schappert and von Hauff [57] "Greenwashing" driving forces Kim et al. [51] Influence of choices and behaviors of consumers on environmental quality Wang et al. [108], Torma [70] Environmental problems and human behavior Alvarez-Suarez et al. [6] Social innovations and sustainable consumption Jaeger-Erben et al. [104], Iran and Müller [56] Attitudes implicit in green consumer behavior Ceglia et al. [4] Behavioral SCP model Dubey et al. [2] Consumption-value gaps and sustainable consumption behavior Biswas [46] Consumer behavior Rezvani et al. [109], Dhandra [41] "Material possession love" consumer behavior Dong et al. [110] Sustainable consumption behavior concept Figueroa-Garcia et al. [111] Sustainable consumption and online shopping Guillen-Royo [112] Behavioral control Ansu-Mensahe and Bein [113], Simeone and Scarpato [71] Motivation to consume for status Ali et al. [114] Adults and young people's sustainable creative competence Kreuzer et al. [115] Rational action theory Yarimoglu and Binboga [35] Values, motivations, and paths involved in the engagement of people who adopt low-carbon lifestyles Carrero et al. [78] In addition, recommendations for the development of future studies addressing research gaps that remain to be addressed are shown in Table 5. The authors of the present review opted to exclude recommendations seen as "generic," such as "replicate the study with a larger sample." Therefore, Table 5 shows potential research subjects that can be explored in the sustainable consumption field.

Topics Recommended for Study Authors
Expanding mental models Sedlacko et al. [59] Exploring other characteristics of consumers Kim et al. [51] Improving questionnaire design and sample selection Wang et al. [108] Developing new studies on adoption of alternative routines and practices Jaeger-Erben et al. [104] Identifying how transcultural differences can create a powerful and synergic system to promote sustainable consumption Ceglia et al. [4] Improving the study by using several case studies or alternative methods and theories Dubey et al. [2] Replicating the study to test generalization in other samples Biswas [46] Examining the effect of motivations that lead to pro-environmental behavior in a more representative sample Rezvani et al. [109] Analyzing the different variables to help understand the relationship between material possession love and sustainable consumption behavior Dong et al. [110] Identifying the variables and projecting scales to measure them Figueroa-Garcia et al. [111] Exploring how "mindfulness" practices can encourage sustainable consumption in schools Bohme et al. [44] Analyzing levels of knowledge and attitudes related to sustainable consumption in students at other universities, taking into account the characteristics of these spaces Ahamad and Ariffin [116] Replicating the study on the role of big data in the collaborative performance of partners in sustainable consumption programs by collecting longitudinal data Dubey et al. [99] The approach used in the interview failed to consider the specific factors of the context, which left opportunities for future studies Huttel et al. [117] Carrying out in-depth analysis of each subdomain to offer detailed suggestions about the topics addressed Shao [118] Evaluating adherence of additional research areas and development of sociotechnical studies Ma et al. [32] Bridging the gaps in "practice theory" research fields; more specifically, addressing how results of the application of this theory differ from those obtained in studies on sustainable behaviors Corsini et al. [119] Examining people with low levels of education to determine to what extent noneducational factors can act as sustainable consumption drivers Ukenna et al. [120] Seeking to confirm the causal relationship between online shopping and well-being Guillen-Royo [112] Examining and analyzing the actual behavior of consumers and connecting the results with the data reported in the original study Ansu-Mensahe and Bein [113] Examining the additional cultural dimensions to obtain more insights Ali et al. [114] Collecting data from interviewees of different levels of education, ages, and cultural origins Dhandra [41] Empirically testing improvement in sustainable behavior Kreuzer et al. [115] Empirically testing sustainable consumption behavior Yarimoglu and Binboga [35] Giving more emphasis to relationships inherent in "mindfulness" and ethical values Geiger et al. [121] Future studies can use the model to compare knowledge of and interest in sustainable products between young people and older people Legere and Kang [42] Considering the effect of "self-caused" and "caused" factors Han [122] Examining how these moral competencies are developed, paying special attention to gender-based differences Valor et al. [45]

Topics Recommended for Study Authors
Repeating the study in other countries and with samples that are representative of different age groups Piligrimiene et al. [123] Developing new studies on second-hand product attitudes, social standards, intentions, and behavior to deepen knowledge about pro-environmental behavior Borusiak et al. [124] Considering profiles of other types of consumers and identifying whether the results of the new studies agree with those of the original Awais et al. [47] Developing new studies on environmental performance by especially taking into account sustainable development goals and SCP Nishitani and Kokubu [52] Exploring the potential of emotional mechanisms in the sustainability domain Tarditi et al. [125] Considering empirical validation of the behavior Kapoor and Dwivedi [107] Addressing the mediator effect of cultural facilitation and focal constructs in countries where sustainable consumption is well-established Carrero et al. [78] Regarding a future sustainable consumption research agenda, there are new opportunities that can help deepen knowledge of the area in the short term and be good focuses of attention for researchers who are planning new studies on this subject. Figure 9 shows these opportunities grouped into research areas. The studies found in the survey carried out for the present review were more focused on elucidating consumer behavior and what influenced people to adopt sustainable consumption practices [104], which created a gap in the understanding of the role of companies in the perpetuation of sustainable consumption. That does not mean that these studies did not exist. However, they were smaller in number and were more oriented toward

Companies and business environments
Role of companies in the perpetuation of consumption

Role of managers and stakeholders in sustainable consumption
In-depth study on the experience of a company in adopting sustainable consumption Case studies on sustainable production Hierarchy of the good practices that are most adopted by companies Analysis of studies published before 2011 The studies found in the survey carried out for the present review were more focused on elucidating consumer behavior and what influenced people to adopt sustainable consumption practices [104], which created a gap in the understanding of the role of companies in the perpetuation of sustainable consumption. That does not mean that these studies did not exist. However, they were smaller in number and were more oriented toward stressing infrastructure changes for adoption of new practices [67] and the associated financial benefits [52], rather than focusing on other contexts or the actual role companies have to play in the face of new concerns about the relationship between consumption and sustainability.
Consequently, this research field would benefit from studies addressing the following topics: (i) managers' concerns about making the companies they work for more sustainable; (ii) the role of stakeholders and stockholders in strategic choices for consumption [99,126]; (iii) case studies on decreases in consumption of resources and materials in production; (iv) ways to make production processes more transparent to the population; (v) companies' ability to engage their public in sustainable consumption; and (vi) even using a method, such as an analytical hierarchy process, to rank good practices that are most commonly used internally by companies that implement sustainable consumption.
It would also be interesting to design studies focused on benchmarking companies and/or specific products in order to make it possible to reach more accurate conclusions about the process of adapting certain organizations to accommodate sustainable consumption, or which barriers hindered this process in specific settings or contexts [127].
Most studies that analyzed consumer behavior surveyed opinions and habits of part of a population, but did not show divisions among consumers, such as the proportion of people who have higher purchasing power compared to a group with lower purchasing power [128]. Therefore, it would be helpful to try to understand how different types and segments of clients behave [129], and their perceptions regarding new types of products [114].
Studies on consumer behavior are always important, because the social phenomenon that is consumption can be different in different locations, which makes it impossible to select a sample that is representative of the world's entire population [130]. In addition to the opportunity to replicate studies in order to understand the behavior of people living in different countries, it may also be possible to carry out analyses that take into account unbridled consumerism [131] and how it can harm the environment in different nations.
More than simply observing consumer behavior, researchers must pay more attention to new consumption phenomena. Because societies are in constant evolution, new factors may influence the actions of populations, and these must be properly measured by means of indicators [132]. Additionally, new tendencies may arise in economies [133] or in the patterns of consumption to be studied, such as reuse of products and shopping in thrift stores [134]. It is also necessary to consider the idea suggested by Ma et al. [32] that additional research areas and sociotechnical studies that advance sustainability theories and practices in developing countries should be part of the examination of SCP.
Finally, it should be emphasized that, because of the scope chosen for the present systematic literature review, only recommendations for future studies pointed out in articles published between 2011 and 2020 were shown. Therefore, it may be important to examine material published before 2011 to compare progress in the research field and analyze whether these studies indicate gaps and whether these unsolved questions remain relevant or applicable at present.

Final Considerations
The present review analyzed a sample of 114 articles published over the past ten years and available on the Web of Science. From the organizational point of view, the concept of sustainable consumption is more related to sustainability and green technologies and agrees with SCP discussions found in the United Nations Sustainable Development Goals.
The articles included in the present review were organized into "research areas" to facilitate grouping of discussion. The most active areas of research were: "people's sustainable behavior", with 61 articles; "public policies and countries", with 21 publications; and "companies and business environments", with 32 articles. Of the 114 publications, 22 focused on mathematical models, 7 were literature reviews, and 85 were empirical studies, of which 57 applied interviews and questionnaires more oriented toward elucidating people's behavior.

Theoretical Implications
Although the results of the present review showed concerns about the impacts of people on sustainable consumption, since most discussions in the selected studies focused on analysis of consumer behavior, one of the main theoretical implications of the present study was shedding light on sustainable consumption in companies and public policies. Some examples were studies in which the researchers sought solutions to understanding the adoption of sustainable consumption by companies and related these consumption practices to the companies' target publics.
Given that different actors have to be engaged in order for the promotion of sustainable consumption to be successful, the authors of the present review suggest that discussions about the role of companies and public policies receive more attention from researchers, because organizations are also important in shaping the development of and changes in sustainable behavior by individuals. Studies involving individuals must continue to be carried out, but there is no doubt that the participation of companies and governments can facilitate the promotion of sustainable consumption in societies as a whole. In order to deepen this discussion, the business perspective must not limit itself to monitoring consumer behavior but must seek to elucidate the motivations that inspire people to develop attitudes that support sustainable consumption. Still, it is necessary to explain how companies themselves can influence their publics to look for products that observe sustainability practices.
The search for sustainable consumption strategies in organizations manifests in attempts to reduce information asymmetry between the parts involved, whether they are part of the production process or of the development of new products. The impact of information asymmetry has been the object of study in public organizations when analyzing whether or not governments have adopted sustainable consumption public policies.
Another relevant theoretical implication was confirmation that the subject of sustainable consumption allows the application of different methodologies in theoretical and practical studies and those involving use of mathematical models. These methods have been applied to issues ranging from sustainable production to solutions for urban mobility and the sharing economy, and have offered new perceptions regarding the problems, solutions, and contexts in which the sustainable consumption can be implemented.

Practical Implications
The issues pointed by the authors cited in the present study highlight the need for strategies that are coordinated between diverse sectors, not only in order to understand what sustainable consumption practices are, but also to create incentives that encourage participation of societies, together with companies and public institutions. Although there were a considerable number of studies about sustainable consumption over the past ten years, there were few studies that actually highlighted the practices applied to the adoption of sustainable consumption. There were even fewer studies that deepened the discussion about the tools and/or processes that must be used to achieve better results in the sustainable consumption area.
Nevertheless, dissemination of new technologies can help production processes, making them more efficient, economical, and sustainable, which may positively impact the creation of products with raw materials that are better for the environment, and procedures that facilitate adoption of sustainable consumption practices. Still regarding companies, a substantial number of studies analyzed SCP, which indicated the existence of great concern about linking sustainable consumption to cleaner production.
Regarding public policies, there is not a direct relationship between the level of urban development and sustainable practices. However, it was shown that studies that delved more deeply into everyday behavior found that people in areas with higher levels of urban development were more prone to engage in pro-environmental behavior. Therefore, without ignoring the role played by individual initiatives of certain groups, it is crucial to develop public and private policies in order for societies to gradually deal more naturally with sustainable consumption. Incentives by companies and authorities are fundamental in changing and promoting new habits.
Companies that adopt sustainable consumption, or measures that encourage it, end up strengthening their image. However, implementing sustainable practices becomes more complex in large companies, and may even imply adjustment in areas such as law, technology, and infrastructure.
Research in the area of sustainable consumption often has the objectives of helping in the process of overcoming barriers to its application and encouraging implementation of sustainable consumption practices in companies and society. In line with that trend, the literature highlighted some recommendations that include recognition by individuals that they are part of the sustainable changes implemented in companies, and ideas for institutional and organizational changes to establish rules and functioning dynamics of production systems. Studies that presented new ideas, theories, and methods included elucidating the behavior of individuals, and addressing the public sphere, which can create incentives for sustainable consumption, and included analysis of different metrics used by companies.

Study Limitations
One of the limitations of the present review was the fact that only articles published in journals in English and available on the Web of Science were considered for selection. Therefore, the authors do not rule out the possibility that there are quality studies on this subject in journals in Spanish or Portuguese on the Web of Science, or even publications in other languages and databases. Additionally, the present review addressed discussions about sustainable consumption found in articles published over the past ten years. Consequently, future studies could have a search strategy that includes more terms, covers a longer period, and includes other databases.
For example, an important aspect that can be explored in future studies is the relationship between price, behaviour, and sustainable consumption. Geiger et al. [121], in this direction, affirms that the employment of sustainability-adapted mindfulness-based intervention (sMBI) may decline materialistic value orientation (MVO), which may lead to more ethical consumption patterns, contributing partly to a sustainable consumption. Purnomo et al. [135], looking at the coffee industry, believes that when consumers have higher knowledge and attention to the products they seek and buy, there can be better competitive conditions to local and more sustainable producers.
Still in this matter, Ülkü and Hsuan [65] believe that conscientious advertising and recycling/reusing modular parts of products can support the reduction of prices and increase of a company's market share. These practices come with the purpose of aligning environmental commitment of consumers and companies, and at the same time offering accessible prices. Therefore, although this is a limitation of this study, there is an opportunity in future research to expand this in-depth review, for example, by converting the topic related to consumers behavioral impact on the strategy of companies, because there can be elements, such as socioeconomic conditions and pro-ecological attitudes, that possibly can relate to consumers' patterns and its relation to market-share, quality, price, and the level of greenness of a product.
Another limitation of the present review was that it did not identify in detail any actions and technical procedures that companies and public institutions can adopt to promote sustainable consumption. This limitation resulted from the characteristics of the analyzed articles, since most focused on consumer behavior. Therefore, for future studies that aim to bridge this gap, the authors recommend carrying out searches that go beyond the traditional literature and include business reports, successful cases, and managers' actions related to adoption of sustainable consumption practices in the organizations they work for. These sources would allow researchers to understand the tools that are most commonly used, and the concerns of companies located in certain environments about sustainability questions.
An additional limitation is that the present study did not consider the need for analysis of multiple variables that directly influence the sustainable consumption actions of companies and people, especially regarding suggestions for future studies. The reason is that public policies, social, economic, ethical, and cultural factors, and individual preferences can motivate populations to develop greater concern with sustainability.
In the public policy sphere, these surveys could be used to find out what abrogated and existing laws of countries can influence sustainable practices. In fact, Figure 5 shows that there is less research carried out on this topic in relation to the others discussed here (consumers and companies), especially in recent years. Additionally, taking into account the issues raised by Koide and Akenjii [80] and Yarimoglu and Binboga [35] concerning a lack of incentives in developing countries, it is important to emphasize that, within the period delimited for the review, no studies were found that focused on public policies that boosted or impaired adoption of sustainable consumption in Latin and South American countries. In our view, these observations are configured as additional incentives for carrying out future research involving public policies and sustainable consumption.
Finally, even though there has been a substantial number of studies oriented toward elucidating consumer behavior, the research field would benefit from studies that carefully consider economic changes and new consumption practices that may appear over the years, and even the role of the media in the construction of perceptions regarding companies and sustainable practices. It would also be interesting to carry out studies involving not only undergraduates in certain institutions or random samples from specific populations but also people from different social classes, to understand how they make their consumptionrelated decisions.