Labeling the carbon footprint of food prompts more sustainable eating behavior

A field trial has shown that labeling the carbon footprint of food prompts people to eat more sustainably.

Labeling the carbon footprint of food prompts people to eat more sustainably: This was the key finding for TRR 266 Accounting for Transparency researchers from LMU Munich, HU Berlin and Aalto University in Finland in a recent field trial. How the information is presented turned out to be the critical factor: The effect was greatest when CO₂ information was visualized as traffic light colors or displayed in the form of cost to the environment.

Field trial at the Leopoldstrasse canteen

The ten-day field trial was conducted at one of the Munich Student Union's largest canteens: the one in Leopoldstrasse. During the experiment, more than 8,000 visitors to the canteen saw not only the usual menu information (such as the prices and main ingredients of each dish), but also details of the carbon footprint.

The form used to present the CO₂ information was changed once a day during the trial period to see which had the greatest influence on consumers' behavior. Some visitors, for instance, were informed of the environmental cost of their lunch in euro terms. On displays, others saw how much of their daily carbon budget was taken up by the meal they chose. Still others were informed of the CO₂ emissions (in grams) caused by the given meal.

These details were flanked by traffic-light-based color coding (in green, yellow and red). The most powerful effect was achieved when visitors learned the cost (in euros) of the environmental damage caused by their lunch. In this way, as much as nearly ten percent fewer CO₂ emissions were caused by meals purchased than when no information about CO₂ emissions was provided.

A starting point for government agencies and companies to support more sustainable behavior

Our experiment makes it clear that information about the carbon footprint can lead to a change in consumers' behavior. This insight in turn can help government agencies and the business community to adopt suitable measures for a more sustainable future. For example, companies could make a voluntary decision to display CO₂ information for food and for other products and services."

Thorsten Sellhorn, Professor of Account, Auditing and Analysis at LMU