RESEARCH Current Research Continuing Education Questionnaire, page 577 Meets Learning Need Codes 3000, 4000, 4160, 5200, and 5370 Obesity, Disordered Eating, and Eating Disorders in a Longitudinal Study of Adolescents: How Do Dieters Fare 5 Years Later? DIANNE NEUMARK-SZTAINER, PhD, MPH, RD; MELANIE WALL, PhD; JIA GUO, MS; MARY STORY, PhD, RD; JESS HAINES, PhD, MHSc, RD; MARLA EISENBERG, ScD, MPH ABSTRACT 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, ex- treme weight control, and self-reported eating disorder. Statistical analysis Multiple linear and logistic regressions. Results Adolescents using unhealthful weight-control be- haviors 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 in- creased 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 behav- iors predict outcomes related to obesity and eating disor- ders 5 years later. A shift away from dieting and drastic weight-control measures toward the long-term imple- mentation of healthful eating and physical activity be- haviors is needed to prevent obesity and eating disorders in adolescents. J Am Diet Assoc. 2006;106:559-568. O besity, disordered eating, and eating disorders are major public health problems among adolescents because of their high prevalence and their poten- tially serious physical and psychosocial consequences (1- 8). Understanding factors influencing these eating and weight-related problems and identifying effective preven- tion strategies are critical issues. One important question relates to the role of dieting. Questions about its effec- tiveness in weight management and its potential for in- creasing risk for unintentional weight gain, disordered eating, and eating disorders have been raised (9-13). Longitudinal studies have the capacity to determine if dieting precedes the onset of obesity, disordered eating, and eating disorders. Longitudinal studies exploring these associations are limited and findings are not con- sistent across studies (14,15). However, the larger studies suggest associations between dieting and the later onset of obesity, disordered eating, and eating disorders (11,13,16,17). In a 3-year longitudinal study on a large sample of adolescent girls and boys, Field and colleagues (13) found that dieters were at increased risk for weight gain compared to nondieters. In two separate 4-year lon- gitudinal studies on middle school girls (18) and on high school girls (16), Stice and colleagues found that dieters were at increased risk for obesity onset. Stice and col- D. Neumark-Sztainer and M. Story are professors, M. Eisenberg is an assistant professor, and J. Haines is a research associate, Division of Epidemiology and Com- munity Health, School of Public Health, University of Minnesota, Minneapolis. M. Wall is an associate profes- sor and J. Guo is a research assistant, Division of Bio- statistics, School of Public Health, University of Minne- sota, Minneapolis. Address correspondence to: Dianne Neumark-Sztainer, PhD, MPH, RD, Division of Epidemiology and Commu- nity Health, School of Public Health, University of Min- nesota, 1300 S Second Street, Ste 300, Minneapolis, MN 55454. E-mail: neumark@epi.umn.edu Copyright © 2006 by the American Dietetic Association. 0002-8223/06/10604-0008$32.00/0 doi: 10.1016/j.jada.2006.01.003 © 2006 by the American Dietetic Association Journal of the AMERICAN DIETETIC ASSOCIATION 559