As a result of colonialism and globalization, many Indigenous groups have transitioned towards a Westernized diet, with significant implications for food security and oral health. This study investigated the experiences of the Kaingang and Guarani Indigenous peoples from the South of Brazil regarding the effects of cultural changes on their food systems and oral status. Focus groups were conducted in each tribe and the methodological framework grounded theory was adopted. The development of categories occurred with reference to Pierre Bourdieu's work. Four themes emerged from the analysis: 1. Contemporary Indigenous identities; 2. Perceptions of food systems; 3. Shared knowledge in the orientation of differentiated assistance in oral health; and 4. Ethnic cultural capital in conflict. The food transition is represented as a form of cultural discontinuity, whereas the ability to redefine identity boundaries contributes to promote food security and oral health.