Beyond the first choice: How (nudged) vegetarian food choices spill over to subsequent food choices

Food choices are not made within a vacuum but depend upon earlier decisions, resulting in spillover effects where subsequent choices are either similar (consistency) or contrasting (balancing). Little is known about spillovers in vegetarian (versus non-vegetarian) choices and how Vegetarian Eating Motives (VEM) or contextual factors influence these patterns. This study explored these dynamics through two online experiments. The first experiment (N = 251) utilized a within-subject design in a sequential three-course meal ordering scenario. The second experiment (N = 439) employed an improved mixed design by varying contextual factors (labeling and availability). Both experiments did not observe spillovers between vegetarian and non-vegetarian choices in neutral contexts. We found evidence of spillover when labeling vegetarian dishes as 'Healthy & Sustainable'. This generated more consistency among individuals with strong VEM but increased balancing among those with weaker VEM (OR = 2.29, 95 % CI = (1.25, 4.19)), without altering overall vegetarian choice rates. Enlarging the availability of vegetarian options at the first choice increased in-the-moment vegetarian selection, yet we find no evidence of balancing at later choices. In sum, we only detect spillovers when vegetarian options were labeled as 'Healthy & Sustainable', with the direction of the spillover depending on an individual's VEM. These findings support availability interventions as an effective strategy for increasing in-the-moment vegetarian selection, while highlighting the need for caution with labeling approaches, since this did not increase vegetarian selection but might generate unintended spillover effects.