How smaller plates reduced hotel food waste by 20%

Intervention Business, 

Abstract

About 1.3 billion tons of food are thrown out every year, in grocery stores, at home, in restaurants and hotels.1 To figure out whether nudges could reduce food waste by hotel patrons, researchers set up a collaboration with restaurants in Nordic Choice Hotels to test two different nudges. The first intervention was reducing the size of the plates used by customers, and the second was signage that encouraged customers to get additional servings. Additionally, an observational study was conducted in the remainder of hotels that were not in the treatment or control groups. Both nudges resulted in a roughly 20% reduction of food waste, and the plate size treatment findings were supported in the observational study.

Rating: 5/5 (Significant results; Easy to implement)

How nudges reduce customers’ food waste in hotels
Condition Result
Control group No statistically significant change 
Using smaller plates (3cm smaller) 19.5% reduction of food waste
Displaying signage at a buffet encouraging patrons to return for additional servings 20.5% reduction of food waste

Key Concepts

Choice architecture: The idea that our decisions are shaped by the way in which choices are presented to us.

Nudges: Any component of the choice architecture that changes our behavior in a predictable way; notably, a nudge must be easy or free to avoid. These are subtle manipulations that we might not even notice.

Observational study: An investigatory method in which participants are merely observed, and no action is taken on the part of the researchers to influence behavior. These can be utilized to find out people’s “real” or natural behavior.

The Problem

From global to local

A significant cause of the current climate crisis is human interference. With almost 8 billion mouths on the planet to feed, it’s not a shock that 34% of all man-made greenhouse gases come from food production.2 One third of all food produced is wasted; however, this reality is often forgotten in our fight against climate change.1 Even the U.N.’s Sustainable Development Goal number 12, Responsible Production and Consumption, falls short of encompassing all the factors that go into food waste.1, 3 Lower food waste rates are not only beneficial to the environment, they can also benefit restaurant finances as they cut down on purchased food.

The potential for behavioral science

While previous studies have shown that choice architecture can be used to predictably change people’s actions, they have not been applied with the focus of reducing food waste for environmental reasons. Only a fraction of global food waste is attributed to retail and consumer settings, but that number is still about 3.9 million tons of food dumped annually. More importantly, it’s preventable.1 A behavioral approach is required in this context, as unnecessary human behaviour is at the center of this issue.

Design

Reporting buffet food waste from 52 hotels

In collaboration with a hotel chain, researchers Steffen Håkon Kallbekken and Sælen implemented their study between June and August 2012. The study has two main components, the field study (which includes the two treatment groups), and the observation study. In each of the three groups, (which includes the control group) there were seven hotel restaurants, and all of them recorded and reported the amount of waste each day throughout the entire period. Kallbekken and Sælem conducted an additional observational study at hotels that were not included in any of the treatment groups to measure the validity of the findings. In the end, they collected data from a total of 52 hotels for data analysis.

Smaller plates and Welcome Back signs

In the first condition, researchers used plates that were 3cm smaller on average than the restaurants’ typical plates, from 24 to 21 cm long. In the second condition, the researchers displayed a sign reading, “Welcome back! Again! And Again! Visit our buffet many times. That’s better than taking a lot once.” This was written in seven languages to accommodate the variety of visitors who stayed at the hotels. Investigators hypothesized that the sign would make it socially acceptable to return to the buffet multiple times, taking advantage of known social norms of behavior.

In the observation study, the plate varied in size from 15 to 28cm, with an average of 24 cm. This component of the study was meant to investigate the relationship between plate size and food waste among untreated hotels, and serve as a comparison against the treatment groups.

The EAST Framework

The researchers were motivated to figure out how to reduce food waste by something as subtle as a nudge, and thus used the EAST Framework. It mandates four main ideas: a policy should be Easy, Attractive, Social and Timely. Further, a policy should be able to be implemented as Easily as possible; it must be Attractive to get people’s attention; it must make use of our natural tendency to be Social and value others’ opinions; it must also be Timely and capitalize on when people are most likely to be receptive to it. Smaller plates and new signage were both easily accessible, not out of place in a buffet environment, capitalized on social norms, and motivated behaviour change at the moment of decision-making for customers – selecting food at the restaurant.

Results and Application

A 20% reduction in food waste for both conditions

When reducing the size of the plates, food waste went down by 19.5%; in the buffet sign condition, food waste decreased by a similar 20.5%. The control group saw no statistically significant change in waste.

Findings from the observational study, in which unrelated hotels’ restaurants were monitored, supported those from the plate condition. The investigators saw that those who used a plate that was 1cm smaller than the average threw away 7.4% less food, and when that scaled up to the same size reduction as condition 1 (3cm), reduction rates were about the same, at 22%.

Environmentally friendly AND cost efficient

Applications for these findings could have meaningful effects for the reduction of food waste globally. It’s financially attractive for hotels, too: smaller plates are cheaper to replace than large ones, and the cost of printing the signs was minimal (only 10-30 needed to be printed for each hotel). Restaurants could also cut down on spending, as they wouldn’t have to buy as much food.

Not only were the nudges easy to implement, environmentally friendly, and less costly for hotels, they had no impact on customer satisfaction. The researchers monitored this component via the hotels’ online survey, having been concerned that patrons wouldn’t like having to take more trips to the buffets, but the rates were effectively constant. While a few questions are left unanswered by this study (for example, implementing the nudges at the same time) the findings are encouraging and marketable for hotel owners and environmentalists alike.

 

Industry Application
Education Childhood obesity is a crisis that is plaguing most developed countries. While getting kids to eat healthier foods is a main concern, implementing smaller plates could prevent them from overeating. Using smaller plates will help ensure that kids are only getting the food that they will eat and would prevent mindless eating.
Health & Wellbeing The same methodology could be implemented in buffets at hospitals for employees. The same benefits that a hotel would see (reduced cost of food, smaller plates) would be observed at a hospital.
Retail & Consumer Grocery stores and farmer’s markets could put up signage that would suggest smaller shopping hauls but more frequent visits. This would encourage people to only buy the produce that they are likely to eat before it goes bad, and also benefit people’s health, as they’ll be getting fresher produce.

Ethics

  • The study utilized a large number of data points and an observational study to measure the reliability and validity of their findings.
  • Anonymity of the hotel guests and even the hotel locations was maintained throughout the duration of the study.
  • The results have positive implications for all living things by helping to reduce the effects of climate change and food inequality.
Yes Room for improvement Insufficient information/Not applicable
Welfare
Does the intervention demonstrably improve the lives of those affected by it? Reducing food waste has positive ramifications for all living things.
Does the intervention respect the privacy (including the privacy of identity) of those it affects? None of the hotels, nor the participants, were identified. Only the hotel chain, Nordic Choice Hotels, was identified.
Does the intervention have a plan to monitor the safety, effectiveness, and validity of the intervention? The researchers conducted an observational study to see whether their findings could be replicated in the “real world.” Patrons’ safety wasn’t threatened.
Autonomy
Does the intervention abide by a reasonable degree of consent? Consumers didn’t know that they were in a study. While they could have seen the poster, they may not have realized that their plates were a smaller size than normal.
Does the intervention respect the ability of those it affects to make their own decisions? Participants were free to get more or less food and were not restricted in their choices to do so.
Does the intervention increase the number of choices available to those it affects? The participants are still able to choose to get as much food as they want, but because it was a nudge study, the goal wasn’t to increase the number of choices available.
Equity
Does the intervention acknowledge the perspectives, interests, and preferences of everyone it affects, including traditionally marginalized groups? It doesn’t make any mention of others’ preferences.
Are the participants diverse? While the study is done in Nordic hotels, it does not mention if the characteristics of the participants were diverse.
Does the intervention help ensure a just, equitable distribution of welfare? As mentioned before, reduced food waste benefits everybody. Less food wasted means more food available to those who need and want it.

Related TDL Articles

Behavioral Science and the Future of Agriculture: While the article above has included an abundance of depressing statistics, what are we to do about the agriculture crisis? In this article, Kaylee Somerville writes about how behavioral science and the future of agriculture are intimately tied to one another, and gives a glimpse of what our circumstances might look like in a few decades.

Mindless Eating: What research did Kallbekken and Sælen reference to support the idea that smaller plates would yield reduced food consumption? Enter the idea of mindless eating. This reference guide article will help you understand all the nuanced behavioral decisions that go into deciding what to eat and how much to eat.

Dancing to the Tunes of a Choice Architect: How much does choice architecture really influence what decisions we make? This article expands upon how choice architecture exists in almost every facet of our lives, and what we can do to stay aware of it.

Sources

  1. Tons of Food Lost or Wasted. The World Counts. (n.d.). https://www.theworldcounts.com/challenges/consumption/foods-and-beverages/food-waste-facts/story
  2. Vetter, D. (2021, March 10). How much does our food contribute to global warming? New research reveals all. Forbes. https://www.forbes.com/sites/davidrvetter/2021/03/10/how-much-does-our-food-contribute-to-global-warming-new-research-reveals-all/
  3. United Nations. (n.d.). SDG 12.3 Food waste index. UN Environmental Programme. https://www.unep.org/thinkeatsave/about/sdg-123-food-waste-index
  4. 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