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?
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.
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.