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  • Writer's pictureMolly Gallant

Trash Talk Post 4: ‘Nudging’ Food Waste Reduction


'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

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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.

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 randomized 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?


  • 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.

  • Cadario, R., & Chandon, P. (2018). Which healthy eating nudges work best? A meta-analysis of field experiments. Appetite, 130, 300–301.

  • Kallbekken, S., & Sælen, H. (2013). “Nudging” hotel guests to reduce food waste as a win-win environmental measure. Economics Letters, 119(3), 325–327.

  • 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.

  • von Kameke, C., & Fischer, D. (2018). Preventing household food waste via nudging: An exploration of consumer perceptions. Journal of Cleaner Production, 184, 32–40.


Recommended citation format: Gallant, M. “Trash Talk Post 4: ‘Nudging’ Food Waste Reduction”. Food Focus Guelph (51), Department of Food, Agricultural and Resource Economics, University of Guelph, August 21st, 2019.



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