title: Weight-control behaviors and subsequent weight change among adolescents and young adult females.
abstract: BACKGROUND
  Little is known about the effectiveness of behavioral strategies to prevent long-term weight gain among adolescents and young adults.
  
  
  OBJECTIVE
  The objective was to assess the relation of dietary and physical activity weight-control strategies, alone and together, with subsequent weight change.
  
  
  METHODS
  This was a prospective study of 4456 female adolescents and young adults aged 14-22 y in the ongoing Growing Up Today Study. Weight-control behaviors, including dietary approaches and physical activity, were self-reported in 2001 and were used to predict weight change from 2001 to 2005.
  
  
  RESULTS
  In 2001-2002, 23.7% of female adolescents and young adults were trying to maintain their weight and another 54.4% were trying to lose weight. Approximately 25% used each of the following weight-control strategies: not eating snacks, following low-calorie or low-fat diets, and limiting portion sizes. In addition, 47.7% reported exercising at least occasionally for weight control. During 4 y of follow-up, participants gained an average of 3.3 kg. None of the dietary approaches to weight control predicted less weight change; however, females who exercised > or =5 d/wk gained significantly less weight than did their peers (-0.9 kg; 95% CI: -1.4, -0.4). The most successful strategy for weight-gain prevention among the females was to limit portion sizes (-1.9 kg; 95% CI: -2.6, -1.1) combined with frequent exercise.
  
  
  CONCLUSIONS
  Our results suggest that physical activity is a necessary strategy for long-term weight control among adolescents and young adult females. Combining dietary weight-control approaches with physical activity is the most effective method for reducing weight gain.
authors.affiliation: Division of Adolescent Medicine, Children's Hospital Boston and Harvard Medical School, Boston, MA 02115, USA. alison.field@childrens.harvard.edu
authors.forename: Alison E
authors.initials: AE
authors.lastname: Field
authors.forename: Jess
authors.initials: J
authors.lastname: Haines
authors.forename: Bernard
authors.initials: B
authors.lastname: Rosner
authors.forename: Walter C
authors.initials: WC
authors.lastname: Willett
mesh_terms: D000293:Adolescent; D000328:Adult; D032763:Behavior Control / Q000379:methods* / Q000523:psychology*; D001827:Body Height; D001835:Body Weight; D004038:Diet, Reducing / Q000706:statistics & numerical data; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D050177:Overweight / Q000453:epidemiology; D015995:Prevalence; D011795:Surveys and Questionnaires; D014481:United States / Q000453:epidemiology; D015430:Weight Gain / Q000502:physiology; D015431:Weight Loss / Q000502:physiology*; D055815:Young Adult