The main objective of this study is to understand the effect of a default nudge on peoples’ meal choices. To decrease the climate and environmental impact of the food system, there needs to be a shift away from animal source food to plant foods. Our main hypothesis is that when the default meal choice is plant-based, a larger proportion of participants will accept this default, compared with the proportion opting out of the default when it is meat-based and actively selecting a plant-based meal. A second hypothesis is that the climate and environmental impact of the group presented the plant-based default will be less than that of the group presented with the meat-based default. We collected data to test these hypotheses by implementing a meal-choice intervention for a campus Greek organization's group dinner, and for a graduate student training meeting. Half of the attendees for each event were informed that there would be meat-based meal, and asked if they wanted to opt-out to a plant-based meal. The other half were informed that there would be a plant-based meal served, and asked if they would like a meat-based meal instead.

A list of participants to be invited to the event will be divided into two random groups and each group emailed a link to an on line RSVP form.

The first group will be provided with a version of the RSVP form that specifies a meal containing meat as the default. In order to receive a plant-based meal at the event, the respondent must opt-out of the meat default by choosing a plant-based meal.

The second group will be provided with a version of the RSVP form with a plant-based meal as the default. In order to receive a meal containing meat at the event, the respondent must opt-out of the plant-based meal default by choosing a meal containing meat.

Some demographic quests were also asked of the participants after the meal selection. After the event, participants were informed of the default intervention.