Short-term nudges and dietary choices at university canteens: information and price interventions

Universities are increasingly seen as promising settings for promoting healthier, more sustainable diets, yet evidence on the effectiveness of behavioural interventions in real-world food environments remains mixed. This paper studies the short-run effect of two types of interventions to encourage plant-based food (lunch) choices at university canteens. The intervention had three treatment arms implemented in selected canteens: (i) an information intervention providing salient environmental and health information, (ii) a price intervention subsidising vegetarian and vegan meals, and (iii) a combined intervention. Using administrative sales data from Charles University, Prague, we analyse meal-level transactions across all university canteens in Prague before, during, and after the intervention. We evaluate the effect of the intervention on the absolute number and the share of vegetarian and vegan meals sold, as well as on the timing of their sell-outs, using a difference-in-differences design with canteen and day fixed effects, while addressing the parallel-trends and SUTVA assumptions. We find that information-based interventions significantly increase the share of plant-based meals sold, primarily through substitution away from meat-based options, without affecting overall sell-through rates. Price subsidies raise demand for vegetarian and vegan meals but are associated with faster stock-outs, indicating supply constraints. We discuss conceptual problems in measuring the treatment effect due to unobserved choices after vegetarian/vegan meals were sold out, focusing our analysis on the sellouts of the vegetarian. Ongoing research combines administrative data from canteens with students’ personal characteristics, allowing us to examine customer segments more prone to the meal switch. The research has direct implications for public food procurement policies seeking to promote sustainable diets through low-cost, choice-preserving measures.

Key messages

• While price subsidies increase demand for sustainable meals, their impact is often limited by early stock-outs, highlighting the need for supply-side coordination in dietary policy.

• Salient information increased plant-based shares by ∼10% by week 2, primarily through a 10% reduction in meat consumption.