Across 3 pre-registered projects, we analysed the relationship between food representations and dietary behaviour to better understand why shifting towards sustainable diets is so difficult. Specifically, we investigated how polarised omnivores and vegans cognitively represent and publicly present meat and plant-based foods. For each project, food descriptions were coded according to whether they contained features about consuming and enjoying food (e.g. ‘rich’, ‘indulgent’, ‘treat’), or to aspects independent of the consumption situation (e.g. ‘healthy’, ‘protein’, ‘eco-friendly’). In Project 1 (NStudy1 = 852; NStudy2 = 3104), Instagram posts about meat foods were described in hashtags with more rewarding consumption language than posts about plant-based foods, which were instead described with more situation independent language – especially identity-focused discourse (e.g. ‘vegan community’). In Project 2 (NExp. 1 = 220; NExp. 2 = 843), participants described ingroup foods (meat dishes for omnivores; plant-based dishes for vegans) with more rewarding consumption features than outgroup foods (plant-based dishes for omnivores; meat dishes for vegans). In contrast, omnivores used more situation independent features for outgroup foods, and vegans more social and political context language (e.g. ‘animal abuse’). In Project 3 (NExp. 1 = 82; NExp. 2 = 913), when trying to make a plant-based dish appealing to omnivores in a hypothetical social media setting, participants used more rewarding consumption language than when appealing to vegans. Despite people thinking about in-group foods in terms of rewarding consumption, plant-based foods are not publicly described in this way, even by vegans. As reward expectations drive food choices, this typical presentation of plant-based foods can hinder mainstream consumer transitions towards sustainable food choices and strengthen dietary group polarisation.