1 Departamento de Nutrição, Faculdade de Saúde Pública, Universidade de São Paulo, Brazil; 2 Núcleo de Pesquisas Epidemiológicas em Nutrição e Saúde, Universidade de São Paulo, Brazil; 3 Departamento de Nutrição Aplicada ,Instituto de Nutrição , Universidade do Estado do Rio de Janeiro, Brazil; 4 Departamento de Medicina Preventiva, Faculdade de Medicina, Universidade de São Paulo, Brazil.
Background: The prevalence of obesity among adolescents in the US has been increasing since 1976 reaching the current value of 15.5%. Obesity essentially results from imbalance between energy intake and energy expenditure but the reasons for the rising in this imbalance in adolescents are not entirely clear. In parallel to this rise, the food items which have shown the highest consumption increase (in regards to total energy) over the last 20 years have been ultra-processed foods (formulations manufactured mostly or entirely from substances extracted from foods or obtained from further processing of constituents of foods) such as snacks, ready-to-eat meals, and sweetened sugar beverages. Therefore, understanding the relationship between obesity and the consumption of ultra-processed foods seems relevant. Methods: We analyzed data of 1056 adolescents (12y to 19y) from a subsample of NHANES (2007-2010), a cross-sectional study of the US population. Our outcome was obesity status defined using as a cut-off point the 95th percentile of the CDC 2000 Body Mass Index growth chart for age and sex. Quintiles of the contribution of ultra-processed food to total daily energy intake was the exposure. Generalized linear models (Poisson family and link log) were employed to analyze the relationship between exposure and outcome controlling for socioeconomic variables and physical activity. Results: The crude risk ratio of being obese progressively increased from 1.40 in the second quintile to 2.53 in the top quintile (p for trend <0.01), regarding the first quintile of ultraprocessed food consumption. After adjusting for socioeconomic variables and physical activity, the association remained statistically significant (p for trend <0.01) with the risk ratio rising from 1.33 in the second quintile to 2.64 in the top quintile. Conclusion: Higher consumption of ultra-processed foods is associated with higher prevalence of obesity among American adolescents.