Brachem et al., 2019
Brachem, J., Krüdewagen, H., & Hagmayer, Y. (2019). The Limits of Nudging: Can Descriptive Social Norms be Used to Reduce Meat Consumption? It's Probably Not That Easy. https://osf.io/preprints/psyarxiv/xk58q
Two preregistered, randomized experiments (N1= 450 and N2= 899) where participants chose a meal from 5 options. They were given a social norm message or not, about veggie/vegan diets being more popular. It didn't work.
On the other hand, exploratory analyses suggested more options led to choosing more plant based foods