Obesity, disordered eating, and eating disorders in a longitudinal study of adolescents: how do dieters fare 5 years later?

OBJECTIVE

To determine if adolescents who report dieting and different weight-control behaviors are at increased or decreased risk for gains in body mass index, overweight status, binge eating, extreme weight-control behaviors, and eating disorders 5 years later.

DESIGN

Population-based 5-year longitudinal study.

PARTICIPANTS

Adolescents (N=2,516) from diverse ethnic and socioeconomic backgrounds who completed Project EAT (Eating Among Teens) surveys in 1999 (Time 1) and 2004 (Time 2).

MAIN OUTCOME MEASURES

Weight status, binge eating, extreme weight control, and self-reported eating disorder.

STATISTICAL ANALYSIS

Multiple linear and logistic regressions.

RESULTS

Adolescents using unhealthful weight-control behaviors at Time 1 increased their body mass index by about 1 unit more than adolescents not using any weight-control behaviors and were at approximately three times greater risk for being overweight at Time 2 (odds ratio [OR]=2.7 for girls; OR=3.2 for boys). Adolescents using unhealthful weight-control behaviors were also at increased risk for binge eating with loss of control (OR=6.4 for girls; OR=5.9 for boys) and for extreme weight-control behaviors such as self-induced vomiting and use of diet pills, laxatives, and diuretics (OR=2.5 for girls; OR=4.8 for boys) 5 years later, compared with adolescents not using any weight-control behaviors.

CONCLUSIONS

Dieting and unhealthful weight-control behaviors predict outcomes related to obesity and eating disorders 5 years later. A shift away from dieting and drastic weight-control measures toward the long-term implementation of healthful eating and physical activity behaviors is needed to prevent obesity and eating disorders in adolescents.