title: Self-determined, autonomous regulation of eating behavior is related to lower body mass index in a nationwide survey of middle-aged women.
abstract: BACKGROUND
  The associations among people's level of autonomy in regulating their eating behaviors, food patterns, and degree of obesity have not been investigated in a general adult population.
  
  
  OBJECTIVE
  Our objectives were to cross-sectionally examine, in a nationally representative sample of adult New Zealand women, the associations between different styles of eating behavior regulation and body mass index (BMI), with specific food and eating habits as hypothesized mediators.
  
  
  METHODS
  During May 2009, a sample of 2,500 New Zealand women aged 40 to 50 years was randomly selected from the nationwide electoral rolls. A 66% (n=1,601) participation rate was achieved. Potential participants were mailed a self-administered questionnaire containing the Regulation of Eating Behavior scale, questions on specific food and eating habits (frequency of binge eating, speed of eating, usual daily servings of fruits and vegetables, usual frequency of intake of several high-fat and/or high-sugar foods), and height and weight.
  
  
  METHODS
  Univariate linear regression models were used to examine the associations among demographic, health and behavioral variables, and BMI. Multivariate linear regression models were developed to investigate the relationships between autonomous and controlled forms of eating behavior regulation and BMI, with specific food and eating habits as mediators.
  
  
  RESULTS
  After adjusting for potential confounders as well as specific food and eating habits that were potential mediators, BMI was statistically significantly lower by 2% (95% CI -2.7% to -1.4%; P<0.001) for every 10-unit increase in autonomous regulation, and statistically significantly higher by 1.4% (95% CI 0.4% to 2.3%; P=0.005) for every 10-unit increase in controlled regulation. The relationships between autonomous regulation and BMI as well as controlled regulation and BMI were only partially mediated by the specific food and eating habits measured.
  
  
  CONCLUSIONS
  Although the direction of causality requires confirmation, the results provide support for the applicability of Self-Determination Theory, and suggest that developing more autonomous motivation for eating behavior is likely to facilitate healthier food habits and lower BMI in middle-aged women.
authors.forename: Sook Ling
authors.initials: SL
authors.lastname: Leong
authors.forename: Clara
authors.initials: C
authors.lastname: Madden
authors.forename: Andrew
authors.initials: A
authors.lastname: Gray
authors.forename: Caroline
authors.initials: C
authors.lastname: Horwath
mesh_terms: D000328:Adult; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005247:Feeding Behavior / Q000523:psychology*; D005260:Female; D015438:Health Behavior; D006306:Health Surveys; D006801:Humans; D008019:Life Style; D016014:Linear Models; D008875:Middle Aged; D009042:Motivation; D009520:New Zealand / Q000453:epidemiology; D009765:Obesity / Q000453:epidemiology / Q000517:prevention & control* / Q000523:psychology*; D026684:Personal Autonomy; D011795:Surveys and Questionnaires