Does unmatching meat and plant-based meals change plant-based meal selection? An evaluation in an online hypothetical randomised trial.

Changes to food environments can influence individuals' food choices. One possible strategy, as yet untested, to increase plant-based (vegan) food selection is to serve "unmatched" plant-based and meat meals (e.g. "Falafel Burger" and "Chicken Pie") rather than "matched" (e.g. "Falafel Burger" and "Beef Burger"). We ran an online hypothetical choice study in the UK and analysed likelihood of selecting matched vs. unmatched plant-based meals. In study 1 meat-eaters (n=704) were randomised to either see two or three main meals throughout, completing a randomised selection of 10 choice tasks, of which five had matched plant-based and meat meals, and five unmatched. In study 2 vegetarian&vegan participants (n=220) all saw 10 choice sets with three main meals: a meat option alongside matched and unmatched plant-based options. Participants' preferences for types of meal (e.g. curry) and protein were also assessed. Meat-eating participants were significantly more likely to choose a plant-based option when meat and plant-based options were unmatched and when more plant-based options were available. The mean selection of plant-based meals for matched and unmatched scenarios was 21.2% and 30.4% respectively when two main meals (one plant-based, one meat) were present and 37.4% and 44.6% respectively when three main meals (two plant-based, one meat) were present. Vegetarians&vegans were equally likely to select matched or unmatched plant-based options when accounting for their meal type and protein preferences. Further research is needed to establish if serving unmatched meals leads to higher plant-based selections for real as well as hypothetical meal choices.