Naturalistic weight-reduction efforts prospectively predict growth in relative weight and onset of obesity among female adolescents.This study examined the prospective relations of naturalistic weight-reduction efforts to growth in relative weight and onset of obesity with data from a community study of female adolescents (N = 692). Initial self-labelled dieting, appetite suppressant/laxative use, incidental exercise, vomiting for weight-control purposes, and binge eating predicted elevated growth in relative weight over the 4-year period. Dietary restraint, self-labelled dieting, exercise for weight-control purposes, and appetite suppressant/laxative use predicted an increased risk for obesity onset. Data imply that the weight-reduction efforts reported by adolescents are more likely to result in weight gain than in weight loss and suggest the need to educate youth on more effective weight-control strategies. (PsycINFO Database Record (c) 2010 APA, all rights reserved).
Weight-loss attempts may be associated with subsequent major weight gain, even when several potential confounders are controlled for. Genetic and familial factors may contribute to this association.
EVIDENCE THAT DIETING IS THE MOST EFFICIENT MEASURE TO PREDICT WEIGHT GAIN
This study examined measures of restrained eating, disinhibition, and emotional eating as predictors of weight gain during the freshman year. Using Lowe's multi-factorial model of dieting, it also examined three different types of dieting as predictors of weight gain. Sixty-nine females were assessed at three points during the school year. Weight gain during the freshman year averaged 2.1 kg. None of the traditional self-report measures of restraint, disinhibition, or emotional eating were predictive of weight gain. However, both a history of weight loss dieting and weight suppression (discrepancy between highest weight ever and current weight) predicted greater weight gain, and these effects appeared to be largely independent of one another. Individuals who said they were currently dieting to lose weight gained twice as much (5.0 kg) as former dieters (2.5 kg) and three times as much as never dieters (1.6 kg), but the import of this finding was unclear because there was only a small number of current dieters (N=7). Overall the results indicate that specific subtypes of dieting predicts weight gain during the freshman year better than more global measures of restraint or overeating.
EVIDENCE THAT DIETING INCREASES PSYCHOLOGICAL STRESS AND CORTISOL, TWO FACTORS KNOWN TO CAUSE WEIGHT GAIN
To test the hypothesis that dieting, or the restriction of caloric intake, is ineffective because it increases chronic psychological stress and cortisol production--two factors that are known to cause weight gain; and to examine the respective roles of the two main behaviours that comprise dieting--monitoring one's caloric intake and restricting one's caloric intake--on psychological and biological stress indicators.
Results: Restricting calories increased the total output of cortisol, and monitoring calories increased perceived stress.
Conclusion: Dieting may be deleterious to psychological well-being and biological functioning, and changes in clinical recommendations may be in order.
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