Which food waste interventions for consumers have the highest impact?

December 11th, 2024

Summary by: Carole Liechti and Jeanine Ammann

From: Agroscope

In 2022, around 1.05 billion tons of food were wasted globally at consumer level, despite the fact that food waste is preventable (United Nations Environment Programme, 2024). Therefore, it is crucial to implement effective measures to tackle food waste at the consumer level and to shift behaviour towards more sustainability and less food waste. Studies have shown that behavioural interventions targeting consumers are effective in reducing food waste and have become increasingly popular in recent years (Caldeira et al., 2019; Jagau and Vyrastekova, 2017; Reynolds et al., 2019). However, effectively reducing food waste requires in-depth knowledge of the impact of the interventions.

To this end, Agroscope researchers conducted a systematic literature review and analysed a total of 49 studies that examined 54 interventions to reduce food waste at the consumer level. Three criteria were evaluated: the intervention type, the study design, and the impact on food waste reduction (Figure 1).

Figure 1: The studies included in this systematic literature review were assessed based on criterion 1 (intervention type), criterion 2 (study design), and criterion 3 (impact on food waste reduction).

Intervention type

We identified 54 interventions in the 49 studies included in this review. Of the 54 interventions included in the review, we found predominantly single-component interventions (83%), while multi-component interventions (17%) were applied less often. Most single-component interventions tested nudging (42%) or knowledge enhancement (24%) strategies. Interventions involving awareness raising, social influence, and incentives were less frequently used. Further, the multi-component interventions mainly used nudges in combination with other types of interventions. The majority of interventions were conducted in households (35%), followed by universities (24%), schools (18%), hotels (9%), retail (6%), hospitals/nursing homes (4%), restaurants (2%), and camping (2%).

Study design

Most of the analysed studies were non-randomized (quasi-experimental) studies (65%). Randomized studies were therefore underrepresented (26%). Of these, only a few were randomized controlled trials (9%). Studies that used multi-component interventions were more likely to be randomized than those using single-component interventions. Non-experimental studies comprised 9% and included national programs and cross-sectional studies.

Impact on food waste

Most interventions led to a statistically significant reduction in food waste (n = 36). Some studies without any reduction used following intervention types: social influence, awareness raising, knowledge enhancement and nudging. Multi-component interventions with nudging proved to be particularly promising for reducing food waste. The highest significant food waste reduction among the 49 studies was achieved by a multi-component intervention with nudging combined with knowledge enhancement. The use of individualized training and personalized solutions with a coach, including prompts such as tips via text message, email, or phone calls, led to a significant reduction in food waste of up to 79% (p = 0.001) (Roe et al., 2022).

Figure 2: Impact of interventions on food waste (n = 54 interventions from 49 studies), with significant reduction, non-significant reduction, and no reduction. Interventions are divided into single-component (nudge, awareness raising, knowledge enhancement, social influence, incentive) and multi-component interventions.

Recommendations

Based on the study results, we propose the following measures to make food waste interventions even more efficient in the future:

  • Further studies outside the home are needed (e.g. airplanes)
  • Reduce selection bias of participants (e.g. students).
  • Inclusion of participants who are not aware of the intervention.
  • Test more interventions with harmonized and robust study designs, such as randomized controlled trials.
  • More studies in which household food waste is measured by third parties (food waste composition analysis)
  • Overall, more multi-component interventions (especially nudges combined with knowledge enhancement) are needed.
  • Testing the long-term effects of interventions to reduce food waste.
  • Increasing the awareness of one’s own behavior (measuring food waste at home)
  • More interventions in supermarkets to positively influence consumer behavior with regard to food waste in households.
  • Increase representativeness of the study populations

Link to access the full publication: https://doi.org/10.1016/j.spc.2024.11.023

References

Caldeira, C., De Laurentiis, V., & Sala, S. (2019). Assessment of food waste prevention actions—Development of an evaluation framework to assess the performance of food waste prevention actions. https://doi.org/10.2760/9773

Jagau, H., & Vyrastekova, J. (2017). Behavioral approach to food waste: An experiment. British Food Journal, 119, 882–894. https://doi.org/10.1108/BFJ-05-2016-0213

Reynolds, C., Goucher, L., Quested, T., Bromley, S., Gillick, S., Wells, V. K., Evans, D., Koh, L., Carlsson Kanyama, A., Katzeff, C., Svenfelt, Å., & Jackson, P. (2019). Review: Consumption-stage food waste reduction interventions – What works and how to design better interventions. Food Policy, 83, 7–27. https://doi.org/10.1016/j.foodpol.2019.01.009

Roe, B. E., Qi, D., Beyl, R. A., Neubig, K. E., Apolzan, J. W., & Martin, C. K. (2022). A Randomized Controlled Trial to Address Consumer Food Waste with a Technology-aided Tailored Sustainability Intervention. Resources, Conservation and Recycling, 179, 106121. https://doi.org/10.1016/j.resconrec.2021.106121

United Nations Environment Programme. (2024). Food Waste Index Report 2024. Think Eat Save: Tracking Progress to Halve Global Food Waste. https://wedocs.unep.org/xmlui/handle/20.500.11822/45230

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