How do defaults and framing influence food choice? An intervention aimed at promoting plant-based choice in online menus.

Nudging consumers towards plant-based foods by making these choices the default option is a promising strategy for effecting sustainable dietary change. In the hypothetical context of online food ordering in a Northern European country, we examined the underlying mechanisms and effectiveness of swapping the default in menus from meat to a plant-based meat alternative. Results showed that pre-selecting a plant-based option in the online setting was not enough to increase choice of plant-based meals alone. Rather, additionally framing the plant-based default as the more sustainable or tasty option was needed to significantly increase choice. While ease was unimportant and held constant in this online setting, endowment and implied endorsement were found to mediate default success such that the positive influence of endowment outweighed the (surprising) negative effect via endorsement. In contrast to general theoretical expectations of default nudges, an endorsement by an online food provider is unlikely to encourage plant-based choices.