Among both age cohorts of girls studied, for example, the prevalence of dieting remained fairly constant from early teen years to early 20s (55.3% to 54.6%) and from mid-teens to mid- to late 20s (57.5% to 59%), Dianne Neumark-Sztainer, PhD, MPH, and colleagues from the University of Minnesota in Minneapolis, found.
In general, the prevalence of dieting and disordered eating was high and remained constant, or increased, from adolescence to young adulthood.
Furthermore, behaviors tended to track within individuals and, in general, participants who engaged in dieting and disordered eating behaviors during adolescence were at increased risk for these behaviors 10 years later, they reported in the July issue of Journal of the American Dietetic Association.
Longitudinal studies of disordered eating patterns from early adolescence to early adulthood are limited in number and scope, and findings have been inconsistent, researchers noted.
Another problem with previous studies, according to Neumark-Sztainer and colleagues, is their "limited generalizability given that most have been conducted within predominantly white samples of women, primarily of high socioeconomic status."
In the current study, researchers included 1,030 young men and 1,257 young women of various ethnic groups and socioeconomic statuses. They were part of the Project EAT-III (Eating and Activity in Teens and Young Adults), a 10-year longitudinal study aimed at examining eating, activity, and weight-related variables among young people.
Participants filled out questionnaires at baseline, five years, and 10 years. Five-year data were not used in this study.
Ten-year follow-up data represented only 48.2% of the original cohort and attrition was not equal across sociodemographic characteristics, researchers reported. They therefore weighted the data to be similar to the original cohort.
The final weighted sample was 48.4% white, 18.6% African American, 19.6% Asian, 5.9% Hispanic, 3.3% Native American, and 4.2% mixed or other race/ethnicity and was well distributed across five levels of socioeconomic status.
Researchers assessed unhealthy and extreme weight control behaviors with the question, "Have you done any of the following things in order to lose weight or keep from gaining weight during the past year?"
Responses categorized as unhealthy weight control behaviors included:
- Ate very little food
- Used a food substitute (powder or a special drink)
- Skipped meals
- Smoked more cigarettes
Responses categorized as extreme weight control behaviors included:
- Took diet pills
- Made myself vomit
- Used laxatives
- Used diuretics
The study cohort included a younger group (mean age 12.8 at baseline and 23.2 at follow-up) and an older group (mean age 15.9 at baseline and 26.2 years at follow-up). About half of girls reported dieting in the past year, compared with about one-fourth of the boys.
Among boys, the prevalence of dieting stayed constant over time in the younger age cohort (28.6% to 25.6%), but significantly increased in the older cohort as participants progressed from middle adolescence to middle young adulthood (21.9% to 34.5%, P<0.001).
Unhealthy weight control behaviors in younger girls remained constant from early adolescence to early young adulthood (48.2% to 50.2%). However, these behaviors significantly decreased from middle adolescence to middle young adulthood, but still remained very high (60.7% to 54.4%, P=0.004).
Approximately one-third of boys reported unhealthy weight control behaviors, and the prevalence remained fairly constant during the study period in both age cohorts (34.8% to 27.6% from early adolescence to early young adulthood, and 27.9% to 29.9% from middle adolescence to middle young adulthood).
Extreme weight control behaviors significantly increased among both cohorts of girls: from 8.4% to 20.4% between early adolescence and early young adulthood and from 12.6% to 20.6% between middle adolescence and middle young adulthood (P<0.001 for both).
These extreme behaviors did not change significantly for the younger cohort of boys. However, there was a significant change from middle adolescence to middle young adulthood (2.1% to 7.3%, P<0.001).
Binge eating increased in the older cohorts of both girls and boys. Among girls, the prevalence increased from 9.9% during middle adolescence to 14.1% in middle young adulthood (P=0.012). Among boys, the prevalence of binge eating increased from 3% in middle adolescence to 5.9% in middle young adulthood (P=0.020).
These behaviors tended to track within individuals over the 10-year period. Tracking was particularly consistent for the older females and males transitioning from middle adolescence to middle young adulthood.
"The tracking of these potentially harmful behaviors suggests that their use is not just a phase that adolescents go through, but instead indicates that early use of dieting and disordered eating behaviors may set the stage for continued use of these behaviors later on," the researchers wrote.
A limitation to the study, according to the authors, is that they did not have data to suggest the frequency of disordered eating behaviors. The fairly large attrition rate also is a limitation, even though the authors used a weighting analysis to compensate for the loss.
The project was supported by a grant from the National Heart, Lung, and Blood Institute.
The authors did not report any conflicts of interest.
- Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planner
Journal of the American Dietetic AssociationSource Reference: Neumark-Sztainer, D et al "Dieting and disordered eating behaviors from adolescence to young adulthood: Findings from a 10-year longitudinal study" J Am Diet Assoc 2011; 111: 1004-1011.