Should we offer oat drink? Exploring availability and positioning as strategies to reduce milk consumption at a self-service lunch restaurant

Dairy products are the second greatest contributor to the environmental burden of food in Europe, surpassed only by meat. The objective of this field study was to explore availability and positioning as strategies to promote the substitution of milk for a plant-based alternative on the coffee counter of a weekday self-service restaurant. Data on consumption of milk and oat drink of 6,147 meals were collected in four different conditions: only milk (control), only oat drink, both beverages on both sides, both beverages on different sides of the coffee counter. Results show a 38% decrease in milk consumption per paying customer on days when both beverages were available compared to control, leading to an estimated 32% decrease in greenhouse gas emissions (GHGE). Contrary to hypothesized, the total volume of beverages was 12% lower on days when both were served compared to control days, causing a 9% decrease in total costs. The ratio of milk by oat drink was also 21% lower when each beverage was served on different sides of the counter compared to when both were served on both sides. Our study suggests that serving a plant-based alternative and creating small barriers to milk are promising strategies to reduce GHGE in day-to-day gastronomic venues.