This blog post discusses our team’s recently published peer-reviewed article. For the full article, please visit this page.

As we have discussed in previous blog posts, food waste is now recognized around the world as a pressing environmental, social and economic issue. Although food waste occurs at all stages of food production and consumption, some estimates suggest that up to 50% of food waste in Canada is generated at the household-level. As awareness around food waste grows, pressure is building to develop effective and timely solutions.

However, evidence-based suggestions and high-quality food waste data remain relatively scarce. Without a solid foundation and understanding of food waste, how can we inform narratives that encourage consumer behaviour change? So far, there is little academic literature that systematically observes household food waste generation in a Canadian context.

Our interdisciplinary team from various departments across campus sought to fill this gap by conducting a study among families with young children living in Guelph, ON.

Study Overview

Throughout the study, all families were asked to keep track of every food purchase receipt – from grocery stores and farmers markets to restaurants and take-away establishments – anywhere that food was purchased. Throughout this period, we collected each families’ household waste including their recycling, garbage and organics. This waste was then audited by a team of very dedicated (and brave!) graduate students in the first year, and by a professional audit company the second year. Each individual food item was separated, recorded and weighed. All food items were also classified as being either avoidable or unavoidable. For example, a whole banana would be peeled, and the peel would be considered unavoidable, whereas the actual banana would be avoidable. Our focus was on the avoidable portion of food waste – any food that was at some point edible. In the end, we had 316 unique avoidable food items. It was this list that formed the basis of our subsequent analysis.

What did we find?

Overall, the average household in our study generated approximately 2.98kg of avoidable food waste per week. Fruits and vegetables made up two thirds of this waste, followed by breads and cereal making up about a quarter of total waste.

That being said, it can sometimes be difficult to visualize food waste in terms of a weight value. In order to further contextualize these results, we examined the dollar value, nutritional losses as well as environmental impacts of what was thrown away.

In our study, one week of avoidable household food waste represented…

3,366 calories.

This is the recommended daily caloric intake for 1.7 children or 2.2 adults. This means that the average household in our study could have provided an additional five adult meals, or 7 child meals based on the edible items they wasted. The items wasted also represented significant losses of fibre, magnesium, calcium, vitamin D, vitamin B12, vitamin C and vitamin A – all nutrients that are often consumed below recommended intake levels in Canada. Weekly wasted food represented 2.3 servings of fibre, 2.5 servings of vitamin D, 1 serving of vitamin B12, 4.8 servings of vitamin C, 1.9 servings of vitamin A, 0.9 servings of calcium and 1.6 servings of magnesium.

In this case, wasted fruits and vegetables represented a significant missed health opportunity.

$18.01.

An extra $18 a week in a family’s pocket could go a long way!

23.3 kg of CO2.

This equates to 1.2 tons of carbon dioxide which is equivalent to one quarter of the emissions from a car being driven for a year, or 2.8 barrels of oil consumed.

6.7 m2 of land and 5000 L of water.

Consider that the average 5-minute shower uses 35 liters of water. Wasted avoidable food items represent close to 143 showers per week!

What does this mean?

These multiple valuation frameworks provide different means of communicating the impacts of food waste to both policy makers and the public at large. Our hope is that these new perspectives, based on detailed observations of family food behaviours rather than estimations derived from system-wide data, will enable more informed and urgent conversations around food waste in Canada.

Article Reference:

von Massow, M., Parizeau, K., Gallant, M., Wickson, M., Haines, J., Ma, D. W. L., … Duncan, A. M. (2019). Valuing the Multiple Impacts of Household Food Waste. Frontiers in Nutrition. Retrieved from https://www.frontiersin.org/article/10.3389/fnut.2019.00143

#foodwaste #Canada #households #valuation #health #economic #environmental

‘Nudge theory’ is a behaviour change approach initially presented by economist Richard H. Thaler and Law Professor Cass R. Sunstein in their popular book “Nudge – Improving decisions about health, wealth and happiness”.

Thaler and Sunstein (2008, p. 6), describe a nudge as:

“any aspect of the choice architecture that alters people’s behavior in a predictable way without forbidding any options or significantly changing their economic incentives. To count as a mere nudge, the intervention must be easy and cheap to avoid. Nudges are not mandates. Putting the fruit at eye level counts as a nudge. Banning junk food does not.”

This “choice architecture” represents all outside forces that may subtly guide individuals’ decisions. Based on this theory, behaviours may be altered by changing the nature of this environment. This manipulation is called “libertarian paternalism” and is meant to improve people’s choices, and their associated outcomes, while also allowing individuals to maintain their freedom of choice.

This theory has been widely applied in nutritional research. Interventions that change the choice architecture of the subject, while maintaining their autonomy, have been developed and tested in order to assist consumers in making healthier food choices.

Given the overlap between food waste prevention behaviours and general food-related choices, it seems likely that nudge theory could also be used to prevent food waste generation at the household-level. The habitual and unreflective nature of food waste behaviours make them highly suitable for nudge-based interventions. However, before getting into this concept more, it is interesting to first consider some of the literature examining nudge theory and healthy food choices.

‘Nudging’ Healthy Food Choices

In a meta-analysis conducted by Arno & Thomas (2016), nudge strategies were found to successfully improve nutritional choices. Chandon and Cadario (2018) build on this concept further by categorizing and labelling the most common nudge interventions developed. Based on this analysis, nudges were broken down into three broad categories.

1. Cognitive

Cognitive nudges work by providing consumers with information and trusting that they will use it to make better choices. An example of this could be making the healthy option more visible. This could be done by including calorie count or nutrition facts on a restaurant menu. These kinds of nudges can be further improved by adding some context, known as evaluative labelling, such as a smiley faces or traffic colours.

Although cognitive (also known as informational) nudges certainly have merit from an educational and ethical standpoint, they have been found to be only a quarter as effective as behavioural nudges.

2. Affective

Affective nudges make more of an appeal to our emotional sides by making healthy food sound more exciting or appealing. Using either signs, displays or else verbal encouragement, consumers can be directed to make better choices. An example of this might be arranging an appealing display of fruits and vegetables.

These strategies were found to be moderately successful at improving food choices.

3. Behavioural

The final category of nudge also happens to be the most effective at changing behaviour. Behavioural nudges work to modify behaviours without necessarily changing what people think or what they want. This method does not require any collaboration or volition on behalf of the individual. An example of this might be enhancements that make healthier options easier to eat – such as pre-cutting fruits and vegetables or perhaps modifying plate size.

Retrieved from: https://www.research-live.com/article/features/be360-nudging-healthy-eating/id/5041153

Nudge-Based Food Waste Interventions

Can these same theories and types of nudges be used to reduce food waste generation at the household-level? Although research remains relatively limited in this domain, some studies have begun to answer this question.

In a study conducted by Kallbekken and Salen (2013) two simple, non-intrusive nudges were tested in their ability to reduce the amount of food wasted in a hotel restaurant. The first intervention tested was simple; a reduction in plate size offered at the buffet. Based on the above criteria, this would be called a behavioural intervention. Previous research has shown that this simple switch reduces portion size as well as subsequent food waste. The second nudge was a direct social cue in the form of a sign at the buffet encouraging guests to help themselves more than once. This was theorized to create the social norm that it was acceptable to revisit the buffet and thus would discourage people from loading too much on their plates at once. Both of these “nudges” relied on influencing consumption norms through external cues.

The results of these nudges were significant, a 20% decrease in food waste. Although these results suggest some promise, these types of nudge interventions would only be relevant in a context where buffet meals are served.

Another study conducted by Shearer et al. (2017) examines a nudge intervention at the household-level, but specifically in terms of food waste recycling, rather than food waste preventing behaviour.

In a randomised control trial, the effectiveness of using stickers as a visual prompt to encourage the separation of food waste was investigated. The study began with a 15-week baseline period where all waste streams were collected and weighed. Participants were then divided into control and treatment groups. In the treatment group, stickers encouraging source-separation of food waste were affixed to the lids of their waste collection bins. After 16-weeks of follow-up collection and weighing post-treatment, researchers found a significant increase in food waste recycling in the treatment group and no change in the control group. This change was found to persist long-term.

The authors conclude the article by suggesting that a small nudge in the form of a sticker prompt may have a sustained impact on food waste recycling rates. This is a simple, feasible and relatively inexpensive behaviour change intervention. However, one can argue that the behaviours required to prevent food waste, rather than divert it, remain quite different. Therefore, this kind of intervention may have less success in preventing household food waste.

Finally, a recent study conducted by von Kameke & Fischer (2018) takes a first exploratory analysis of the possibility of nudge interventions to reduce household food waste. Using a questionnaire, researchers sought to better understand consumers’ preferences and interest in changing their food waste behaviour. Results suggest that respondents were open to behaviour change and were interested in learning more about the topic. Authors use these results to indicate that nudging could be a suitable tool for reducing household food waste. However, they are unable to report on the actual efficacy of the nudging approach as no intervention was implemented.

Further research should build on these results by testing the nudging approach through intervention studies that measure actual food waste before and after the implementation of nudges

In summary, there is evidence to suggest that behavioural nudges may be the most effective at encouraging behaviour change and thus should be more thoroughly examined. However, based on the presented research the question remains; can nudges be effective at preventing food waste at the household-level?

References

• Arno, A., & Thomas, S. (2016). The efficacy of nudge theory strategies in influencing adult dietary behaviour: A systematic review and meta-analysis. BMC Public Health, 16(1), 1–11. https://doi.org/10.1186/s12889-016-3272-x
• Cadario, R., & Chandon, P. (2018). Which healthy eating nudges work best? A meta-analysis of field experiments. Appetite, 130, 300–301. https://doi.org/10.1016/j.appet.2018.05.170
• Kallbekken, S., & Sælen, H. (2013). “Nudging” hotel guests to reduce food waste as a win-win environmental measure. Economics Letters, 119(3), 325–327. https://doi.org/10.1016/j.econlet.2013.03.019
• Shearer, L., Gatersleben, B., Morse, S., Smyth, M., & Hunt, S. (2017). A problem unstuck? Evaluating the effectiveness of sticker prompts for encouraging household food waste recycling behaviour. Waste Management, 60, 164–172. https://doi.org/10.1016/j.wasman.2016.09.036
• von Kameke, C., & Fischer, D. (2018). Preventing household food waste via nudging: An exploration of consumer perceptions. Journal of Cleaner Production, 184, 32–40. https://doi.org/10.1016/j.jclepro.2018.02.131

Human-Computer Interaction (HCI) or Human Machine Interface (HMI) is a growing area of research that has begun addressing issues related to ecological sustainability. Given the environmental impacts of food waste, some researchers have begun developing technologies that seek to reduce household food waste generation.

From fridge cameras to “smart” bins, a new era of food waste technology is emerging. However, prior to being implemented on a large-scale, it is important to assess and test these technologies with consumers. In this blog post, I take a look at three studies exploring new technologies designed to reduce household food waste.

Negotiating Food Waste: Using a Practice Lens to Inform Design 

Ganglbauer, Fitzpatrick, & Comber (2013) conducted a study to first better understand household food waste behaviours, and to then test a novel technology designed to reduce food waste. A relatively small-scale study, 14 households were recruited for interviews and house tours to observe and measure food waste generation. Next, 5 households had a fridge camera installed for one month to assess its ability to reduce food waste.

Dubbed the FridgeCam, this technology involves a mobile phone attached to the inside of a refrigerator door. For every second the fridge door is open, an accelerometer sensor in the phone triggers the camera and several pictures are taken and uploaded directly to a dedicated webpage. Users can then access the latest 15 captured photos either through their smart phones or on their computers.

Researchers expected the app to be most often accessed via mobile devices in order to allow users to access the information on the go – perhaps while shopping or meal planning. However, far more often, users accessed the FridgeCam on desktop devices in order to ensure it was still working, to show the program to others or else as a memory aid prior to going shopping. Although the device was not used as expected, it assisted in demonstrating the reality of everyday integrated practices and where values within food management, consumption and disposal were acted upon.

Designing beyond habit: opening space for improved recycling and food waste behaviors through processes of persuasion, social influence and aversive affect

In another novel study, Comber & Thieme (2013) investigated the effects of a garbage bin camera designed to promote conscious reflection on waste disposal intentions and behaviours through social influence and aversive effect. In this context, waste was viewed as a habitual behaviour that can be interrupted and over time, altered.

The BinCam is a two-part system where a mobile phone is attached to the lid of a kitchen garbage can. When the lid is closed, the device’s accelerometer is triggered and takes pictures of the waste. These photos are then uploaded to a Facebook page and can be immediately viewed by all BinCam members. This Facebook platform was designed to leverage participant engagement and social influence. The second part of the technology enabled the tagging of the number of both recyclable items and the number of food items. Using this, improvements in waste behaviours were also tracked and visual feedback was provided to each household.

The technology was designed to specifically target individuals between the ages of 18-35 who are typically under-aware of recycling issues. However, in this sample the particpants claimed to already be very aware of recycling issues. Researchers believed this bias resulted in little behaviour change. Rather than actually changing behaviour, the technology enabled increased self-reflection on waste disposal practices.

Fridge Fridge on the Wall: what Can I Cook for Us All? An HMI study for an intelligent fridge

In a study conducted by Bucci et al. (2010) a new Smart Fridge product was researched and developed. Viewed as an intersection between sociology and technology, the goal was to have a technology that seamlessly integrates into everyday life and supports users in their daily tasks.

“In this scenario the user is at the supermarket but she forgot the shopping list. She requested a real-time updated list to her fridge and received it by an sms on her mobile phone” (Bucci et al. 2010)

Referred to as the ZmartFRI, the smart fridge technology is a coupled display system between a fridge and the user’s mobile device. Meant to become a family information hub, the fridge is able to alert users to product expiration dates, suggest recipes based on foods that are available or about to expire, fill in and send by SMS or email the house’s shopping list and send and post messages for the house residents. The ZmartFri is able to do all of this via a RFID antenna and a reader inside to read each product that has a smart label attached to it. Although the prototype is still virtual, it represents a promising avenue for further research.

It seems technology is well on its way to facilitating improved awareness and conscientiousness of waste disposal practices. Although it is difficult to asses their ability to actually alter food waste practices based on the study design of the presented work, this area presents promising avenues for future research.

References

• Bucci, M., Calefato, C., Colombetti, S., Milani, M., & Montanari, R. (2010). Fridge fridge on the wall: what can I cook for us all?, 415. https://doi.org/10.1145/1842993.1843093
• Comber, R., & Thieme, A. (2013). Designing beyond habit: Opening space for improved recycling and food waste behaviors through processes of persuasion, social influence and aversive affect. Personal and Ubiquitous Computing, 17(6), 1197–1210. https://doi.org/10.1007/s00779-012-0587-1
• Ganglbauer, E., Fitzpatrick, G., & Comber, R. (2013). Negotiating food waste. ACM Transactions on Computer-Human Interaction, 20(2), 1–25. https://doi.org/10.1145/2463579.2463582

“A successful design intervention will contribute to nudge people to reduce their food waste, perhaps without them having to change their attitude, be educated or raise their effort greatly.”

1. Technology that helps people plan their food purchases and consumption while keeping an overview of food they have at home.
2. Packaging and storing solutions that extend product shelf-life.
3. Information and awareness campaigns.
4. Systemic change to the food system through the development and implementation of policy.

• Ganglbauer, E., Fitzpatrick, G., & Comber, R. (2013). Negotiating food waste. ACM Transactions on Computer-Human Interaction, 20(2), 1–25. https://doi.org/10.1145/2463579.2463582
• Hebrok, M., & Boks, C. (2017). Household food waste: Drivers and potential intervention points for design – An extensive review. Journal of Cleaner Production, 151, 380–392. https://doi.org/10.1016/j.jclepro.2017.03.069
• Stöckli, S., Niklaus, E., & Dorn, M. (2018). Call for testing interventions to prevent consumer food waste. Resources, Conservation and Recycling, 136(November 2017), 445–462. https://doi.org/10.1016/j.resconrec.2018.03.029

“the unintended result of multiple moments of consumption dispersed in space and time across other integrated practices such as shopping and cooking, which are themselves embedded in broader contextual factors and values”.

• Ganglbauer, E., Fitzpatrick, G., & Comber, R. (2013). Negotiating food waste. ACM Transactions on Computer-Human Interaction, 20(2), 1–25. https://doi.org/10.1145/2463579.2463582,
• Hebrok, M., & Boks, C. (2017). Household food waste: Drivers and potential intervention points for design – An extensive review. Journal of Cleaner Production, 151, 380–392. https://doi.org/10.1016/j.jclepro.2017.03.069,
• Neff, R. A., Spiker, M. L., & Truant, P. L. (2015). Wasted food: U.S. consumers’ reported awareness, attitudes, and behaviors. PLoS ONE, 10(6), 1–16. https://doi.org/10.1371/journal.pone.0127881,
• Parizeau, K., von Massow, M., & Martin, R. (2015). Household-level dynamics of food waste production and related beliefs, attitudes, and behaviours in Guelph, Ontario. Waste Management, 35, 207–217. https://doi.org/10.1016/j.wasman.2014.09.019,
• Pearson, D., Mirosa, M., Andrews, L., & Kerr, G. (2017). Reframing communications that encourage individuals to reduce food waste. Communication Research and Practice, 3(2), 137–154. https://doi.org/10.1080/22041451.2016.1209274,
• Qi, D., & Roe, B. E. (2016). Household food waste: Multivariate regression and principal components analyses of awareness and attitudes among u.s. consumers. PLoS ONE, 11(7), 1–19. https://doi.org/10.1371/journal.pone.0159250,
• Quested, T. E., Marsh, E., Stunell, D., & Parry, A. D. (2013). Spaghetti soup: The complex world of food waste behaviours. Resources, Conservation and Recycling, 79, 43–51. https://doi.org/10.1016/j.resconrec.2013.04.011,
• Schanes, K., Dobernig, K., & Gözet, B. (2018). Food waste matters – A systematic review of household food waste practices and their policy implications. Journal of Cleaner Production, 182, 978–991. https://doi.org/10.1016/j.jclepro.2018.02.030,
• Shaw, P., Smith, M., & Williams, I. (2018). On the Prevention of Avoidable Food Waste from Domestic Households. Recycling,3(2), 24. https://doi.org/10.3390/recycling3020024
• Stöckli, S., Niklaus, E., & Dorn, M. (2018). Call for testing interventions to prevent consumer food waste. Resources, Conservation and Recycling, 136(November 2017), 445–462. https://doi.org/10.1016/j.resconrec.2018.03.029

There’s no way around it: food waste is a complex, multi-faceted problem. The various drivers and contributors to this issue are both diverse and prevalent.

Perhaps as complicated – if not more – is trying to study this topic.

When considering the food waste problem, a good starting point is to assess the reality of the situation. How bad are things…really? Answering this question may seem an obvious first step. However, getting good data is far from easy.

In this post, I’m going to discuss some of the different methods we commonly see in the literature for quantifying food waste.

Up first are Consumer Surveys.

A common and budget-friendly method of assessing an issue like this is to design a survey aimed at addressing specific research questions. However, there are some significant drawbacks to this method.

For example, a survey conducted in the United States looking at consumers’ reported awareness, attitudes and behaviours surrounding food waste found some interesting results. Among their participants, they observed widespread self-reported awareness and knowledge about food waste to be an issue. Additionally, approximately three-quarters of respondents stated that they waste less food than the average American (Neff, Spiker, & Truant, 2015).

Does this mean that the remaining one-quarter of Americans – apparently not surveyed – are indeed responsible for the majority of food waste generation in America?

Highly unlikely.

What’s more likely is one of two options, both of which the literature identifies as commonly contributing to inaccurate consumer perceptions of food waste.

First and foremost, we see in the literature that food waste is the result of both conscious and unconscious behaviours. It is quite possible that consumers simply are not aware of just how much food they waste, and are therefore unable to report on it accurately. Furthermore, a study conducted by our research group in Guelph, ON found, through a series of interviews, that consumers are reluctant to identify themselves as someone who wastes more food than others in their social circle (Parizeau, von Massow, & Martin, 2015).

The second theory is that, given the social bias around food waste, participants in surveys are reluctant to tell the truth – especially if the truth is ugly (and when it comes to food waste, it often is). Instead, they will give what they perceive to be the “socially-desirable” response.

This gap between what people say they do and what they actually do has prompted researchers to look for other methods to assess consumers’ food waste.

Which brings us to method #2: Kitchen Diaries.

This method requires households to maintain a daily log of the food waste they generate. Detailed comments such as weight or volume of food waste, time of disposal, destination of waste, state of food, and reason for discard are recorded. This method allows a more fulsome assessment of household food waste and when used alongside a survey can provide some additional demographic and attitudinal details.

Although more accurate and detailed than a simple survey, the self-reporting nature of this method may still lead to some inaccuracies. Under-reporting (be it intentional or unintentional) and recruitment bias are significant limitations to this approach. In fact, a study conducted in the UK using kitchen diaries found that consumers underreport quantities of food waste by up 40% (Quested et al., 2013)! It is also difficult recruiting for this kind of study. The daily logs can be quite labour-intensive and unless the participants are highly-engaged or there is a significant incentive for participation, drop-out rates can be high.

In order to circumvent the issues with self-reporting, researchers have turned to the streets – where lie carts, bins and bags of all shapes and sizes waiting to be examined.

You guessed it, this brings us to option three for food waste data collection: Waste Composition Studies.

Waste composition studies involve physically separating, weighing, and categorizing food waste. This method is useful in overcoming under-reporting issues and participant biases. By collaborating with local waste services, this can be a highly effective and objective method of quantifying food waste.

Inevitably, there remain some limitations with this approach as well. This method only accounts for food waste destinations associated with municipal solid waste streams. Any waste disposed of down the drain or using backyard composting will be missed with this technique. Furthermore, the extensive resources, cost and time as well as strong municipal partnerships required for this method to work well are often barriers.

There are trade-offs with each approach I’ve discussed here. However, the potential to perfect and refine these methods certainly exists. As this area of research grows, we can look forward to better and more accurate data demonstrating the true breadth and complexity of the food waste problem. Furthermore, with improved data collection methods we can better inform interventions designed to promote sustainable behaviour and reduce food waste generation.

References

Neff, R. A., Spiker, M. L., & Truant, P. L. (2015). Wasted food: U.S. consumers’ reported awareness, attitudes, and behaviors. PLoS ONE, 10(6), 1–16. https://doi.org/10.1371/journal.pone.0127881

Parizeau, K., von Massow, M., & Martin, R. (2015). Household-level dynamics of food waste production and related beliefs, attitudes, and behaviours in Guelph, Ontario. Waste Management, 35, 207–217. https://doi.org/10.1016/j.wasman.2014.09.019

Quested, Ingle, R., Parry, A., 2013. Household Food and Drink Waste in the United Kingdom 2012. WRAP.