title: Variation in dietary intake and physical activity pattern as predictors of change in body mass index (BMI) Z-score among Brazilian adolescents.
abstract: OBJECTIVE
  To assess whether changes in dietary intake and physical activity pattern are associated with the annual body mass index (BMI) z-score change among adolescents.
  
  
  METHODS
  The study was conducted in public schools in the city of Piracicaba, Sao Paulo, Brazil, with a probabilistic sample of 431 adolescents participating in wave I (2004) (hereafter, baseline) and 299 in wave II (2005) (hereafter, follow-up). BMI, usual food intake, physical activity, screen time, sexual maturation and demographic variables were assessed twice. The association between annual change in food intake, physical activity, screen time, and annual BMI z-score changes were assessed by multiple regression.
  
  
  RESULTS
  The study showed a positive variation in BMI z-score over one-year. Among variables related to physical activity pattern only playing videogame and using computer increased over the year. The intake of fruits and vegetables and sugar-sweetened beverages increased over one year, while the others variables showed a reduction. An increased consumption of fatty foods (β = 0.04, p = 0.04) and sweetened natural fruit juices (β = 0.05, p = 0.03) was positively associated with the rise in BMI z-score.
  
  
  CONCLUSIONS
  Unhealthy dietary habits can predict the BMI z-score gain more than the physical activity pattern. The intake of fatty foods and sweetened fruit juices is associated with the BMI z-score over one year.
authors.affiliation: Pontifical Catholic University of Campinas (PUC), School of Nutrition,, Campinas,, Brazil.
authors.forename: Carla C
authors.initials: CC
authors.lastname: Enes
authors.forename: Betzabeth
authors.initials: B
authors.lastname: Slater
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D001938:Brazil; D002648:Child; D004032:Diet; D004435:Eating; D005260:Female; D005544:Forecasting; D006801:Humans; D008297:Male; D009043:Motor Activity