Double nudges can accelerate the transition towards more climate-friendly diets – experiment involving default meals and carbon footprint information

There is an increasing focus on the importance of reducing red meat consumption for environmental as well as health reasons. In this study, we have assessed how consumers' choice of protein source in a meal could be affected by two nudging tools. The first nudge consisted of serving a plant-based steak as the default option instead of beef, alongside placing the plant-based steak at the top of the list of possible protein sources. The second nudge was to provide information about the food's carbon footprint. Based on a representative survey among 2000 Danish respondents, we found a significant effect of both nudges, with substantially fewer respondents choosing ground beef for their meal. An interesting twist in the substitution pattern was found when beef was the default option, as carbon information made respondents shift from beef to chicken, pork, or fish, whereas when a plant-based steak was served as default, carbon information resulted in more diverse consumption – including also substitution to the plant-based option. We also found that respondents with a personal norm of feeling a moral obligation to reduce their contribution to climate change, who were sensitive to other's opinions, stated a high awareness of challenges related to climate change, or bought a lot of organic food were more likely to avoid beef and/or be affected by the carbon footprint information. Finally, one third of the sampled consumers were not willing to forgo beef. • Changing the default or providing information reduced the carbon footprint of food choice. • Applying two nudges in combination reduced the carbon footprint substantially. • Changing the default induced more diverse substitution than information provision. • NAM variables helped to elucidate the effect of carbon footprint information. • One third of the respondents were not willing to forgo beef.