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Where to start fighting the food waste problem? Identifying most promising entry points for intervention programs to reduce household food waste and overconsumption of food

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Highlights

  • Food waste related behaviors have specific effects on household food waste and overconsumption of food.

  • Behaviors’ effects and their performance levels vary between food groups.

  • Overconsumption of food should also be considered as an issue reaching beyond the food waste problem.

Abstract

Preventing household food waste and overconsumption of food represents a crucial leverage point for the promotion of global environmental sustainability with various food waste related behaviors (i.e. planning, shopping, storage, preparation and consumption practices), which should be taken into account when developing appropriate intervention programs.

In order to identify the most promising entry points for intervention development, we conducted an online survey (N = 402) to quantify effects’ strength of various food waste related behavioral categories on food waste outcomes as well as on overconsumption outcomes referring to specific, environmentally relevant food groups (i.e., meat, dairy products and bakery products). In line with previous research, we identified (1) food waste preventing consumption practices referring to leftovers, (2) food waste preventing consumption practices referring to expired/ suboptimal food, and (3) food waste preventing shopping practices as characterized by effects of significance and meaning on food waste outcomes and/ or overconsumption outcomes referring to these food groups. Additionally, these three behavioral categories have been found to be characterized by low performance levels and, therefore, hold high potentials for the promotion of behavioral changes by intervention programs.

In addition to providing valuable results for intervention initiatives, our study also provides empirical evidence and draws attention to appropriate developments in food waste research by considering (1) specific behavioral characteristics, (2) specific food characteristics, and (3) sufficiency strategies and overconsumption of food as an independent issue reaching beyond the issue of household food waste to improve the sustainability of the modern food system.

Introduction

Globally, 1.3 billion tons per year of all food that is produced for human consumption are lost or wasted (see e.g., Gustavsson et al., 2011) with industrialized countries producing high amounts of food waste, i.e. food that is discarded/ not consumed in time being suitable for human consumption (see e.g., Buchner et al., 2012; Lucifero, 2016; Parfitt et al., 2010; Priefer et al., 2016; Stuart, 2009; Thyberg and Tonjes, 2016). Furthermore, studies conducted, for example, in Germany (e. g., Kranert et al., 2012), Italy (e. g., Buchner et al., 2012), Switzerland (e. g., WWF Schweiz, 2012) or in the European Union (EU; e. g., Lucifero, 2016; Stenmarck et al., 2016), unanimously indicate private households as main contributors of food waste. For example Stenmarck et al. (2016) estimated 53% of the total EU food waste coming from households.

Aside from relevant economic and social consequences (see e.g., Food and Agriculture Organization of the United Nations, 2013 for details), high amounts of household food waste also contribute significantly to global environmental problems. (1) In addition to environmental consequences associated with food waste disposal (see e. g., Stuart, 2009), high amounts of food waste represent high amounts of unnecessary global food production, resulting in high amounts of unnecessary global environmental impacts, like unnecessary amounts of greenhouse gas emissions, water consumption, land use as well as unnecessary threats to natural biodiversity, both on land and in water (Food and Agriculture Organization of the United Nations, 2013). In consequence, significant reductions of household food waste can be seen as a crucial leverage to increase global environmental sustainability (West et al., 2014). Thus, the United Nations defined global food waste prevention at the consumer levels (in addition to food waste prevention at the retail levels and the reduction of food losses along production and supply chains, including post-harvest) as an important Sustainable Development Goal (SDG 12.3; United Nations, 2015). But to meet this challenge, we need a clear understanding of the drivers of household food waste.

Even though research on the drivers of household food waste is growing in frequency – especially during the last decade (see e g., Chen et al., 2017; Porpino, 2016; Schanes et al., 2018), it still remains relatively scarce (Roodhuyzen et al., 2017; Stefan et al., 2013; Van Doorn, 2016). Nonetheless, a relevant issue regarding household food waste is already shared by most researchers (e. g., Quested et al., 2013; Roodhuyzen et al., 2017; Schanes et al., 2018; van Geffen et al., 2016): comparable with other forms of household pro-environmental behavior (e. g. decreasing household’s energy consumption by household members’ performance of several energy saving behaviors like switching off the light when leaving a room), “[…] the generation of food waste is best viewed not as a single behavior but as the result of multiple behaviors that can increase the likelihood or amount of food being wasted. These behaviors relate to many different aspects of food’s journey into and through the home: planning, shopping, storage, preparation and consumption of food […]. This means that by the time an item of food is thrown away, the opportunity to prevent that food from becoming waste has usually passed, i.e., the action (or actions) leading to the waste may have been some time, often many days, in the past” (Quested et al., 2013). Therefore, the amount of household food waste (i. e., food waste outcome) finally represent the delayed result of household members’ performance of such various food waste related behaviors, which are typically seen as immediate drivers of food waste outcome (e. g., Roodhuyzen et al., 2017).

When trying to identify more underlying drivers of food waste outcome, most researchers are looking for effects of individuals’ attitudes towards food waste (e. g., Stancu et al., 2016; Stefan et al., 2013), sociodemographic features of household members/ households (e. g., Baker et al., 2009; Consumer View GmbH, 2011; Edjabou et al., 2016; Graham-Rowe et al., 2015; Hamilton et al., 2005; Herath and Felfel, 2016; Jörissen et al., 2015; Koivupuro et al., 2012; Parizeau et al., 2015), or other potential drivers on food waste outcome. Of course, such an outcome focused research approach is very promising, already resulting in relevant findings regarding the underlying drivers of food waste outcome. But considering household members’ performance of various food waste related behaviors as immediate drivers of food waste outcome, an alternative research approach seems also appropriate: since specific behaviors or at least specific behavioral categories are generally characterized by specific underlying drivers (i.e., specific costs and benefits; see e. g., McKenzie-Mohr, 2000), each food waste related behavior or at least behavioral category, should also be characterized by its specific underlying drivers. For example, food waste related shopping practices referring to impulsive purchases due to quantity discounts in supermarkets could be strongly determined by the individual’s preference for economical grocery shopping (see e. g., Aschemann-Witzel et al., 2015; Schmidt, in press). Instead, the consumption of expired (but probable still edible) food could be determined strongly by the individual’s perceived health risks regarding consumption of expired food (see Section 4.1.2 for details), while the individual’s preference for economical grocery shopping could be irrelevant for this specific behavior. Thus, by focusing on effects of potential underlying drivers on food waste outcomes, it seems quite difficult to discover such specific behavioral characteristics. So, in order to further identify underlying drivers of household food waste, we should consider such specific behavioral characteristics by also using a behavioral research approach considering specific drivers of various food waste related behavioral categories resulting in specific findings, which can finally be integrated into a complex, but comprehensive pattern of drivers of household food waste. But in order to do so, initially, we need to get a deeper understanding of effects’ strength of various food waste related behavioral categories on food waste outcome.

Keeping in mind that those food waste related behavioral categories that are characterized by stronger effects on household food waste outcome (i. e., causing higher amounts of household food waste outcome than other food waste related behavioral categories), represent more effective entry points for intervention programs that try to optimize peoples’ behavioral performance in order to decrease food waste outcome, it seems quite obvious to further focus on underlying drivers of these more effective behaviors. Thus, more information about effects’ strength of various food waste related behavioral categories on food waste outcome is needed in order to identify the most promising entry points for future intervention programs. Therefore, we conducted a study trying to quantify effects’ strength of various food waste related behavioral categories on food waste outcome.

Additionally, empirical data about the number of people performing various food waste related behaviors (i.e. performance levels of various food waste related behaviors or behavioral categories) could provide further insight into the most promising entry points for future intervention programs to reduce household food waste (see e. g., Dietz et al., 2009; Klöckner, 2015). For example, low performance levels of food waste related shopping practices referring to avoidance of impulsive purchases represent higher potential for desired behavioral changes than already high performance levels. Thus, in order to use resources wisely, intervention programs should focus on food waste related behavioral categories not only characterized by strong effects on food waste outcome, but also by low performance levels. Therefore, our study should also provide information on the performance levels of various food waste related behavioral categories.

Apart from considering specific behavioral characteristics in order to further identify underlying drivers of household food waste, we also have to consider specific food characteristics, only sometimes considered by previous research on household food waste so far (e. g., Aschemann-Witzel et al., 2018; de Hooge et al., 2017; Wilson et al., 2017). Since research shows both, diverse amounts of household food waste and different amounts of consumption regarding various food groups (e. g. meat vs. vegetables and fruits, see e. g., Food and Agriculture Organization of the United Nations, 2013), differences in an individual’s performance of food waste related behavioral categories regarding various food groups seem also obvious and are already indicated by some empirical work (e. g., Aschemann-Witzel et al., 2015, 2018; Wilson et al., 2017). For example, food waste related shopping practices referring to impulsive purchases due to quantity discounts in super markets, which could be strongly determined by an individual’s preference for economical grocery shopping, could be performed differently regarding food groups characterized by higher prices (e. g., beef) compared to cheaper food groups (e. g., conventional produced dairy products, like milk, yoghurt etc. or bakery products, like bread). So, it seems reasonable to assume some food specific differences in performance levels of various food waste related behavioral categories as well as some further food specific differences in effects’ strength of various food waste related behavioral categories on food waste outcome. Therefore, we also considered a food specific research approach in our study when measuring performance levels of various food waste related behavioral categories as well as when quantifying effects’ strength of various food waste related behavioral categories on food waste outcome.

In order to improve the sustainability of the modern food system, different strategies can generally be used (Allievi et al., 2015): (1) The efficiency strategy focuses on the improvement of resource productivity that is often related to increased economic growth and no necessary changes in values or in consumer preferences. (2) The consistency strategy tries to link natural and industrial metabolisms and, therefore, aims at qualitative changes in production and consumption patterns by resource substitution and adaption to natural resource flows (Schäpke and Rauschmayer, 2014). (3) In contrast to the other strategies, sufficiency strategies focus on the demand side of the food system by emphasizing consumers’ responsibility to restrict their consumption of natural resources and, therefore, the amounts of consumed food. Although sufficiency policies are not very popular due to worries about related restrictions in individual well-being and quality of life, taking into account relevant shortcomings of efficiency and consistency strategies (Schäpke and Rauschmayer, 2014), sufficiency strategies – when conducted carefully and related to appropriate motives for changes – seem to be a promising approach for improving the sustainability of the modern food system. Thereby, reducing food waste outcome can be seen as one way to move towards sufficient food consumption. But reaching beyond the food waste issue, sufficient food consumption also implies that most affluent consumers should substantially reduce their levels of consumption in amounts that are just enough for ideal health in order to reach the sustainable level (Boulanger, 2010). Although it seems not possible to further define such sufficient food consumption by directly measurable/ objective values (i. e., referring to caloric intake), this issue should still be considered for intervention practices in order to further promote sustainable food consumption. Therefore, we also wanted to integrate the general concept of sufficient household food consumption in our study. Thereby, we especially refer to food which is bought in higher amounts than usually consumed in a household (i. e., overconsumption of food), no matter if food is finally discarded (i.e., food waste), shared with others or even consumed by household members themselves in order to prevent food waste.

Previous research already considered the issue of overconsumption of food as a driver for food waste outcome (e. g., Roodhuyzen et al., 2017). But in addition to this approach, examining overconsumption of food as an independent outcome variable as well could also be useful: apart from food waste related shopping practices (e. g., impulsive purchases due to quantity discounts in supermarkets) that represent a conscious overconsumption of food, it seems appropriate to also expect effects of other food waste related behaviors/behavioral categories on overconsumption of food: for example, food waste related planning activities (e. g., planning meals in advance and using a shopping list) could be used as effective measures to decrease overconsumption of food. Furthermore, food waste related storing activities (e. g., storing food in front of cupboards in order to prevent overlooked food) could prevent unconscious overconsumption of such overlooked food. Therefore, we also examined effects’ strength of various food waste related behavioral categories on overconsumption of food in households (hereinafter referred to as overconsumption outcome) in addition to the food waste outcome in our study.

Taken together, the main objective of our study was to provide insight into the most promising entry points for intervention programs in order to reduce household food waste and overconsumption of food. Therefore, we wanted to quantify effects’ strength of various food waste related behavioral categories on food waste outcomes as well as on overconsumption outcomes referring to specific food groups. Additionally, we wanted to provide further information on different potentials for behavioral changes by examining performance levels of various food waste related behavioral categories referring to specific food groups. Thereby, the following hypotheses were formulated:

H1a

Among various food waste related behavioral categories there will be behavioral categories characterized by effects of high significance and meaning (2) on food waste outcomes, while other behavioral categories show no significant/ meaningful effects on food waste outcomes.

H1b

There will be different effects of significance and meaning of food waste related behavioral categories on food waste outcomes depending on the food group.

H2a

Among various food waste related behavioral categories there will be behavioral categories characterized by effects of high significance and meaning on overconsumption outcomes, while other behavioral categories show no significant/ meaningful effects on overconsumption outcomes.

H2b

There will be different effects of significance and meaning of food waste related behavioral categories on the overconsumption outcomes depending on the food group.

H3a

Among various food waste related behavioral categories, there will be behavioral categories characterized by lower/ higher performance levels and, therefore, also by higher/ lower intervention potentials.

H3b

There will be different performance levels for the same food waste related behavioral categories depending on the food group.

Section snippets

Selection of food groups

In order to select specific food groups for our study, we examined climate footprints of conventionally produced food to identify food groups characterized by high environmental impacts (see e. g., Dietz et al., 2009; Klöckner, 2015). Since we conducted our study with a German sample (see Section 2.3 for details), we considered data on such environmental impacts based on information of the Federal Ministry for the Environment Nature Conservation and Nuclear Safety (2018): food groups

Results

Before presenting the results concerning our hypotheses, the following section starts with some preliminary analyses verifying variables’ plausibility and comparability (i.e., randomization check) of the survey’s subgroups.

Summary and possible implications for food waste prevention initiatives

In order to identify the most promising entry points for developing effective intervention programs to prevent household food waste and overconsumption of food, we examined various food waste related behavioral categories referring to specific, environmentally relevant food groups (i. e., meat, dairy products, and bakery products). We identified three behavioral categories characterized by effects of significance and meaning on food waste outcomes and/ or overconsumption outcomes referring to

Conclusion

Taken together, our study not only provides empirical evidence regarding the most promising entry points for the development of effective intervention programs to prevent household food waste and overconsumption of food, but also for appropriate developments in food waste research in general: (1) Thus, presented data support our recommendation to consider specific drivers of various food waste related behaviors or at least behavioral categories through a behavioral research approach in order to

Acknowledgements

We would like to thank all those who scientifically or practically supported our project. Special thanks go to SoSci Panel-team who gave us valuable input during the preparation of our survey.

(1) In addition to households, there are also other sectors contributing to the mentioned ecological consequences by causing food waste on other levels of the food supply chain: following Stenmarck et al. (2016) other sectors also contributing to EU’s food waste are processing (causing 19% of the total EU

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