2. Household Food Waste—How to Avoid It? An Integrative Review

Why do people waste food at home and how can it be prevented? Answers to these questions are relevant, as most food in the developed world is wasted at consumer level (Stenmarck et al. 2016). Stimulating people to lower their food waste levels is challenging and requires a thorough understanding of the behavioural drivers and obstacles to change. In general terms, there are two perspectives one can take to understand behavioural change; an individualistic or a societal perspective. Whereas the former focusses on understanding individuals’ motivation to aim for change and the implementation of this aim, the latter focusses on understanding the influences of societal structure (e.g. modern society) on steering collectives of people to change behaviour. This chapter takes an individualistic perspective and reviews literature on drivers and constraints for individuals to reduce their household food waste. Insights from the societal perspective can be found elsewhere (e.g. Butler et al. 2014; Halkier 2013; Hargreaves 2011).

Practitioners have already implemented interventions, usually awareness-raising campaigns , to stimulate food waste reduction at home (e.g. Love Food Hate Waste, Stop Spild Af Mad, Zu gut für die Tonne). These campaigns are impressive in their outreach and multifaceted nature and several have shown to be (in part) successful (Stöckli et al. 2018). Yet, in most cases these campaigns lack a theoretical basis, proper monitoring and effectiveness measures, making it impossible to deduce which elements drive behavioural change (see, e.g., Stöckli et al. 2018). This is unfortunate as setting up interventions is time consuming and costly and the incorporation of empirical insights is likely to increase the potential for success. Therefore, this chapter will translate the reviewed insights on the drivers and constraints for behavioural change into guidelines and suggestions for interventions with impact. This chapter does not contain new data, but instead contributes to recent work (e.g. Hebrok and Boks 2017; Stöckli et al. 2018), by making a distinction between interventions that steer towards setting an intention to lower food waste levels and interventions that steer towards implementing such an intention. This distinction will improve effective intervention development, as people in different stages towards (deliberate) behavioural change are best served by different types of interventions. People without a set intention to lower food waste levels will benefit most from interventions that stimulate intention setting and not from those that stimulate intention implementation and vice versa.

Put simply, household food waste results from buying more food than is consumed. Yet, food is rarely discarded directly after shopping. Rather, it is discarded after performing a complex set of behaviours, each of which increases the likelihood to waste (Principato 2018; Quested et al. 2013) (see Fig. 2.1). Understanding these household management behaviours helps to identify what interventions should target. This section first discusses the behaviours linked to food waste and then focusses on its drivers.

There are reasons to believe that people do not want to waste food (Roodhuyzen et al. 2017), as they consider it a waste of money (Abeliotis et al. 2014; Neff et al. 2015; Rispo et al. 2015) and morally wrong (Abeliotis et al. 2014; Graham-Rowe et al. 2014). Consequently, it makes people feel guilty (Abeliotis et al. 2014; Graham-Rowe et al. 2014; Neff et al. 2015; Stancu et al. 2016). Yet, this does not mean that people consciously set a goal to reduce their waste levels, as this goals’ importance should be seen relative to their other valued goals. Several aspects influence how important a certain goal is, that is attitude, problem awareness, behavioural influence and responsibility as well as social norms. These aspects will be discussed in turn.

Attitude : How problematic a person finds it to waste food is reflected by his or her thoughts and feelings (e.g. guilt) towards the issue. Attitude has been shown to be a strong predictor of intention (Ajzen 2011) and thus goal setting. Attitude towards food waste is predominately negative (Roodhuyzen et al. 2017). Yet, the variation in attitude among individuals still influences how much food they waste. Thus, the more negative a persons’ attitude, the less food they waste (Stancu et al. 2016; Stefan et al. 2013; Van Geffen et al. 2017).

Problem awareness: Problem awareness may influence attitudes and intentions as well as actual behaviour (Bamberg and Möser 2007; Principato 2018). In the case of food waste, people generally underestimate the scope and the consequences of global food waste levels on the environment and food distribution (Eurobarometer 2014; Secondi et al. 2015), and additionally they underestimate the amount of food they waste themselves (Abeliotis et al. 2014). This affects how much they waste, as greater problem awareness is linked to more waste prevention behaviours (Principato et al. 2015) and lower waste levels (Stancu et al. 2016; Stefan et al. 2013; Williams et al. 2012). Although the latter has not been consistently found with regards to the awareness of the consequences of food waste, this did not always had a significant effect of waste levels (Van Geffen et al. 2017). Generally, awareness of economic consequences (i.e. the costs of their food waste) is often more important and more prevalent than awareness of social or environmental consequences (Graham-Rowe et al. 2014; Neff et al. 2015; Stancu et al. 2016; Van Geffen, Sijtsema, et al. 2016).

Behavioural influence and responsibility: For a behavioural intention to be set, people need to be aware of their behavioural influence (Bamberg and Möser 2007; Klöckner and Blöbaum 2010). If this is absent, people tend to feel that their behaviour is insignificant (Fransson and Garling 1999). A lack of behavioural influence is a common issue with pro-environmental behaviours, where solutions (i.e. lowering the environmental impact of the food system by avoiding waste) are a consequence of the collective, rather than the individual. Another common issue with pro-environmental behaviours is that people do not feel responsible for being part of the solution. Due to this lack of perceived responsibility, no intention to change is formed (Nielsen 2017). To the best of our knowledge, no study has yet looked at the effect of behavioural influence or perceived responsibility on food waste levels.

Social norms: There are two types of social norm beliefs that influence behaviour: the injunctive social norm and the descriptive social norm (Cialdini et al. 1991). The injunctive social norm refers to people’s beliefs of how others who are important to them think about food waste, that is, beliefs on how strongly these important others disapprove of waste behaviour. This social norm does not appear to convincingly influence household management behaviours (Stefan et al. 2013; Visschers et al. 2016) or waste levels (Van Geffen et al. 2017), but may influence intentions to prevent waste (Graham-Rowe et al. 2014; Russell et al. 2017; Stancu et al. 2016). The descriptive social norm refers to the beliefs that important others waste food or not. In other socially desirable behaviours, this norm strongly influences behaviour (Cialdini and Goldstein 2004; Goldstein et al. 2008), and a similar result is found with regard to food waste behaviours (Van Geffen et al. 2017), with a single exception (Graham-Rowe et al. 2015).

In summary, people are more likely to set a goal to prevent food waste when it is considered important enough. This perceived importance is influenced by a person’s attitude, problem awareness, behavioural influence and responsibility as well as social norms.

As already touched upon, there are two reasons why abilities and opportunities are needed to implement the goal to reduce food waste. First, they are vital to perform food waste preventing behaviours effectively and second, they can facilitate acting upon multiple (food-related) goals at once.

The skill to plan accurately: Food waste is essentially acquiring more than needed. Planning (e.g. making shopping lists or measuring how much to cook) can prevent overbuying and overcooking, but only when people accurately predict how much is needed. Accurate planning is difficult as it involves incorporating many varying aspects, such as who will be joining the meals, which portion sizes are appropriate, which products will be fancied, which foods are in stock and what is the food’s current shelf-life status. People who feel more confident about their ability to plan accurately are more likely to perform behaviours that prevent food waste and waste less (Van Geffen et al. 2017).

The knowledge to prolong shelf life: Most wasted foods are perishable, such as vegetables, fruits and bakery products (Quested et al. 2011). The shelf life of these foods is influenced by how they are stored, for example at ambient temperature or cooled (fridge/freezer). Even though people often feel confident about their storing abilities, they frequently store products incorrectly (Plumb et al. 2013). For example, people tend to maintain the temperature of their refrigerator too high (Aschemann-Witzel et al. 2015) or do not use the product’s packaging to prolong its shelf life (Plumb et al. 2013). This can lead to foods losing their flavour or spoiling sooner than necessary (Quested et al. 2011). This makes consumption less likely as people find taste and looks important.

The skill to estimate food safety: People often feel insecure about their ability to estimate food edibility (Brook-Lyndhurst 2011; Farr‐Wharton et al. 2014) and tend to overestimate food safety risks (Grunert 2005), causing foods to be perceived as unsafe before they actually are (Grunert 2005; Tsiros and Heilman 2005). This reduces the likelihood that foods are eaten, as it reduces the number of mealtimes that occur before the food is spoilt or perceived as spoilt. People are risk averse when it comes to food safety, but also dislike discarding edible foods. This (paradoxically) often results in people leaving their potentially unsafe foods in the fridge, until they are certain the food is spoilt (Evans 2012).

Date labels are a guideline for estimating food safety. Unfortunately, many people are confused about these labels and erroneously believe that use-by and best-before dates have a similar meaning (Graham-Rowe et al. 2014; Terpstra et al. 2005). Additionally, date labels are often unclear and difficult to find on the package, which further increases confusion (ICF 2018). Recent insights confirm that the different types of date labels increase the likelihood that foods are wasted (Wilson et al. 2017).

Another way to estimate food safety is to rely on the smell, taste or look of the food. This behaviour is known to reduce waste levels (Terpstra et al. 2005) and is therefore seen as a useful skill to advocate. There are more strategies to estimate food safety than the two discussed here (e.g. relying on days after purchasing or opening). Interestingly, people who use many different methods are more likely to waste food (Parizeau et al. 2015). This may be caused by a higher tendency to classify foods as waste (Parizeau et al. 2015), but may also reflect risk averseness with regard to food-borne illness. Correcting the misperceptions regarding date labels, as well as improving people’s ability to estimate food safety based on their own senses, is likely to lower waste levels (Quested et al. 2011; Terpstra et al. 2005).

The skill to cook (creatively): Adequate cooking skills lower waste levels. These skills lead to fewer cooking accidents (Evans 2011) and simplify using all foods in time, including leftovers (Aschemann-Witzel et al. 2015). With improved cooking skills, people are more able to create tasty dishes, making it easier to prevent food waste. Thus, people who perceive their cooking skills as adequate have less household food waste (Van Geffen et al. 2017).

Dynamic lifestyle: People often lack time to perform food waste preventing behaviours due to demanding lifestyles. They feel pressure to balance multiple goals both related and unrelated to food, such as raising children, work, social activities and household chores (Evans 2012; Quested and Luzecka 2014; Watson and Meah, 2012). It is found that experiencing time pressure is linked to higher waste levels (Mallinson et al. 2016). Additionally, day-to-day life can be unpredictable, making planning inaccurate (Evans 2012; Watson and Meah 2012). Unforeseen work or leisure activities as well as changes in the plans of household members (and their appetites) can increase uncertainties. As a result, even motivated and skilled individuals may not implement food waste preventing behaviours, or implement them but without the desired results.

Available food supply: Perishable food products can vary in quality, which makes taste and remaining shelf life unpredictable. This uncertainty increases the cognitive resources needed to prevent waste, if prevention is possible at all. Another aspect that influences waste levels is the portion sizes offered in the shops. In some cases, the desired portion size is not present, or only at a higher per-unit price. Both options encourage people to buy more than needed (Quested and Luzecka 2014). If sizes are too large, this also has an indirect effect on waste generation, as individuals are more willing to accept waste from larger packaging sizes (Wilson et al. 2017).

Accessibility of shops: Another food infrastructure aspect is accessibility. The geographical density of shops around the household combined with their opening hours may influence food waste levels. Households without easy access to shops are more likely to waste as they need to buy larger quantities in one go, increasing the likelihood to buy more than needed (Abeliotis et al. 2014; Evans 2011).

Equipment at home: It is assumed that the availability and size of storage equipment (i.e. fridge, freezer and storage boxes) at home influence waste levels. More possibilities to store food in an appropriate way may increase the likelihood that food is eaten before becoming spoilt. Yet, the opposite may also occur as people with more storage space may be likely to stock too much food. These effects may cancel each other out, which would account for the reported non-significant effects (Van Geffen et al. 2017), although more research is needed to confirm this. Additionally, kitchen appliances (e.g. blenders or toasters) can lower food waste levels as they provide the opportunity to turn old, disliked products into tasty ones (Mattila et al. 2018).

To summarise, abilities and opportunities can hinder or support people to reduce their waste levels effectively and efficiently. In particular, abilities can help people to act upon food waste prevention and other valued goals simultaneously, for instance when they are able to plan accurately, prolong shelf life, estimate food safety and cook creatively. Opportunities can hinder or support people in preventing food waste, as they influence the amount of resources needed to perform the corresponding behaviours. These refer to lifestyle dynamics, food supply availability, shop accessibility and equipment at home.

In the previous sections, the behaviours causing food to become waste and the drivers of these behaviours have been discussed. These are important first steps in the development of effective interventions, as they identify which problematic behavioural aspects should be changed. Another important aspect is deciding which intervention design is most suitable, as some interventions are more suited to move people towards goal setting, whereas others are more suited to facilitate goal implementation (see Table 2.1).

This chapter reviewed the latest insights on the drivers and constraints for behavioural change towards food waste reduction into guidelines and suggestions for interventions with impact. It made a distinction between interventions that encourage goal setting to reduce food waste levels and interventions that encourage goal striving. It can be concluded that it is difficult to motivate people to actively reduce their food waste levels, despite their strong negative perceptions towards this issue. This is primarily because of the nature of food waste prevention, as this normative goal is difficult to act upon when hedonic goals and gain goals are also activated. Therefore, to successfully steer people towards food waste reduction, interventions should not (solely) provide informational awareness-raising campaigns, as people are already concerned about the issue. Rather, people are best served by interventions that focus on making food waste prevention more salient (relative to their other valued goals), for instance by providing prompts or commitment. Additionally, interventions should focus on facilitating goal striving, by improving people’s abilities and opportunities to handle food effectively. Thus, interventions should enable people to handle food in such a way that they can prevent food waste while also acting upon their other valued goals, without the need to spend more resources. This could be done by providing people with instructions, as well as altering their surroundings to make food waste reducing behaviours easier to perform. To be certain which interventions will be most effective in reducing household food waste levels, we encourage scholars to further investigate the effectiveness of different (combinations of) interventions. In order to do so, we want to stress the relevance and importance of incorporating monitoring and measurement methods when implementing an intervention, as only then the interventions’ effectiveness can be evaluated; for information on this issue see Van Herpen et al. (2016), Reynolds et al. (2019).

Finally, it is important to note that this chapter has not discussed the variety of practicalities one should think about when setting up an intervention. It is out-of-scope to give a conclusive overview of all practicalities of concern, but for more information see Reynolds et al. (2019). However, an important issue we want to highlight is specifying the target audience in terms of (socio)demographics (Reynolds et al. 2019), as this identification will steer decisions on which communication channel should be used (e.g. social media, newspapers) as well as who/what should be the source of the intervention (e.g. government, retail, famous role model) (Klöckner 2015). Without taken this into account, one risks setting up potentially effective interventions which does not reach its appropriate audience.

With the provided insights in this chapter we hope to have given guidelines to develop and implement effective intervention to reduce household food waste.