Weight Control Behaviors and Dietary Intake among Adolescents and Young Adults: Longitudinal Findings from Project EAT

Background Cross-sectional research has found that dieting during adolesence and the use of extreme weight control behaviors are related to less healthful dietary patterns; however, little is known regarding longitudinal relationships. Objective To describe patterns of weight control behavior over 5 years and examine relationships with nutritional outcomes in adolescents and young adults. Design Population-based, longitudinal study in Minnesota. Youth completed Time 1 surveys in 1998-1999, and Time 2 surveys were completed in 2003-2004. Subjects/setting The Project EAT (Eating Among Teens) survey and the Youth and Adolescent Food Frequency Questionnaire were completed by 1,242 females and 1,007 males in school classrooms at Time 1 and by mail at Time 2. Outcome measures and statistical analyses performed Generalized linear modeling was used to predict each Time 2 outcome of interest (ie, meal and snack frequencies and dietary intake) across patterns of healthful and unhealthful weight control behavior (ie, never-engaging, stopping, starting, and persisting). Results Approximately 45% of females and 17% of males reported persistent use of unhealthful weight control behaviors at both time points. Persisting to use only healthful weight control behaviors was reported by 10% of females and 15% of males. Among females, persistent use of unhealthful weight control behavior was associated (P<0.05) with measures of poorer dietary intake (eg, lower intakes of calcium and vegetables) and less frequent meals, whereas persistent use of healthful weight control behavior was associated with measures (P<0.05) of better dietary intake (eg, less fast food and fewer sugar-sweetened drinks). Among males, few associations were observed between dietary intake and either unhealthful or healthful weight control behavior. Conclusions Health professionals should guide youth who have weight concerns by encouraging healthful eating habits to achieve or maintain appropriate weight and nutrition goals. J Am Diet Assoc. 2009;109:1869-1877.