The main goal of this study was to verify relationships between cognitive restraint, priorities in food choice, consumer perceptions, and engagement in slimming process, on willingness to buy foods with nutrition claims (NC). Online questionnaires were answered by 454 consumers over 18 years of age. Cognitive restraint, uncontrolled eating and emotional eating were measured by the Three-Factor Eating Questionnaire-R21. The Eating Motivation Survey was applied to evaluate food choice motives. Consumers' willingness to buy and perceived healthiness were assessed by structured scales. A structural equation model using partial least squares was used to evaluate the impact of different factors on willingness to buy foods with NC. Perceived healthiness impacted positively willingness to buy all foods with NC. Natural concerns had a positive impact on willingness to buy sugar-free chocolate, no sugar added paçoca (peanut sweet), high-protein yoghurt, high-fibre crackers, lactose-free milk and gluten-free bread. Cognitive restraint and engagement in a slimming process positively impacted willingness to buy sugar-free chocolate, high-protein yoghurt, gluten-free bread and light requeijão (Type of cream cheese). Yet, weight control concerns in food choices had a positive impact on willingness to buy light requeijão, high-protein yogurt, no sugar added paçoca and sugar-free chocolate. However, health concerns negatively impacted willingness to buy gluten-free bread, lactose-free milk and high-fibre crackers. The consequences of such perceptions and related factors on food choice and consumption are discussed. The present findings highlight the importance of extending the discussion on food labelling, as well as the careful regulation of the presence of NCs in ultra-processed foods.