Teen eating behaviours continue into adulthood

Adolescents who diet and develop disordered eating behaviours (unhealthy and extreme weight control behaviours and binge eating) carry these unhealthy practices into young adulthood and beyond, according to a study conducted by University of Minnesota researchers and published in the Journal of the American Dietetic Association.

"The findings from the current study argue for early and ongoing efforts aimed at the prevention, early identification, and treatment of disordered eating behaviours in young people," commented the lead investigator, Dianne Neumark-Sztainer, PhD, MPH, RD, Professor, Division of Epidemiology & Community Health, School of Public Health, University of Minnesota.

"Within clinical practices, dieticians and other health care providers should be asking about the use of these behaviours prior to adolescence, throughout adolescence, and into young adulthood. Given the growing concern about obesity, it is important to let young people know that dieting and disordered eating behaviours can be counterproductive to weight management. Young people concerned about their weight should be provided with support for healthful eating and physical activity behaviours that can be implemented on a long-term basis, and should be steered away from the use of unhealthy weight control practices."

The study

Using data from 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, investigators from the Division of Epidemiology & Community Health, School of Public Health and the Department of Paediatrics, University of Minnesota, examined the records for 1,030 young men and 1,257 young women. One third of participants (29.9%) were in early adolescence (mean age = 12.8 years) at the beginning of the study and were in early young adulthood (mean age = 23.2 years) at the 10-year follow-up. Two thirds of participants (70.1%) were in middle adolescence (mean age = 15.9 years) at the beginning and were in middle young adulthood (mean age = 26.2 years) after 10 years.

Subjects were asked about dieting, extreme weight control behaviours such as fasting, using food substitutes and skipping meals, and binge eating with loss of control. Additional socioeconomic, gender, age, and race/ethnicity data was also collected.

Dieting more common among girls

About half of the females reported dieting in the past year compared to about a fourth of the males. The prevalence of dieting remained fairly constant from adolescence through young adulthood for females in both age groups. Among males, the prevalence of dieting stayed constant over time in the younger age cohort, but significantly increased in the older cohort as they progressed from middle adolescence to middle young adulthood (21.9% to 27.9%). In the younger females, unhealthy weight control behaviours remained constant from early adolescence to early young adulthood. Among older females, unhealthy weight control behaviours showed a statistically significant decrease from middle adolescence to middle young adulthood, but still remained very high (60.7% to 54.4%). Approximately one-third of males reported unhealthy weight control behaviours, and the prevalence remained fairly constant over the study period in both age cohorts.

For extreme weight control behaviours, significant increases from adolescence to young adulthood were found in females for both age cohorts and for the older cohort of males. Among females, the use of extreme weight control behaviours increased 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. For the older males, extreme weight control behaviours increased from 2.1% in middle adolescence to 7.3% in middle young adulthood.

These behaviours tended to track within individuals and, in general, participants who engaged in dieting and disordered eating behaviours during adolescence were at increased risk for these behaviours 10 years later. Tracking was particularly consistent for the older females and males transitioning from middle adolescence to middle young adulthood. The tracking of these potentially harmful behaviours suggests that their use is not just "a phase" that adolescents go through, but instead indicates that early use of dieting and disordered eating behaviours may set the stage for continued use of these behaviours later on. - (EurekAlert!, June 2011)

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