Introduction: The type of food consumed during adolescence has a significant impact on the development of chronic diseases, including, oral diseases and obesity. It is therefore justified to study the rate of missing, decayed and filled teeth (DMFT), index body mass index (BMI) and knowledge of oral health in adolescents. Objectives: To characterize the type of food intake in adolescents; assess the association between BMI and type of food, DMFT and knowledge on oral health. Methods: An epidemiological cross-sectional study conducted on a random sample of clusters (schools) of 661 adolescents (56.3% girls and 43.7% boys) with mean age of 13.2 years (SD = 1,139) to attend public schools in the central region of Portugal. Material: a questionnaire was used to collect information about anticariogenic, cariostatic and cariogenic food consumption frequency while a clinical observation was made of the mouth for evaluation of the DMFT index, according to WHO criteria. Assessment of anthropometric data (weight and height) and determination of body mass index (BMI). Results: The DMFT index is 2.23 (SD = 2.48). Mass Index (BMI) has an average value of 21.23 (DP = 3.543). Most adolescents have a moderate anticariogenic food intake (50.7%), cariostatic food intake (57.5%) and high cariogenic food intake (73.1%). Adolescents with a higher BMI consume less cariogenic foods (r = -0.1343, p = 0.001) while adolescents with a higher value of DMFT consume more cariogenic foods (r = 0,160, p = 0.000). The data reveals that the consumption of cariogenic foods explains 1.8% of the variance in BMI and 2.6% of the DMFT. Adolescents who consume less foods with cariogenic effect have better knowledge on oral health (r = -0,165, p = 0.003), and have a higher BMI (r = -0.1343, p = 0.001), while adolescents who consume more cariogenic food have a poorer DMFT index (r = 0,160, p = 0.000). The data on consumption of cariogenic foods explains 2.7%, 1.8% and 2.6% of the variance of knowledge in oral health, BMI and DMFT. Conclusion: Adolescents who consume more cariogenic foods have less knowledge of oral health and a worse DMFT index. An educational intervention in oral health and nutrition is relevant in order to attempt to get better health outcomes with relatively lesser resources.