Physical Activity, Mental Health, and Weight Gain in a Longitudinal Observational Cohort of Nonobese Young Adults

Objective: To investigate the relationship among moderate-to-vigorous physical activity (MVPA), mental health symptoms, and weight gain in young adults. Methods: Fifty-nine healthy men and women (age 26.8 +/- 4.7 years, body mass index [BMI] 22.4 +/- 2.3 kg/m(2)) were assessed at baseline and year 2. Weight, BMI, fat mass by dual-energy X-ray absorptiometry, anxiety and depression by the SCL-90, and MVPA by accelerometry were assessed. Sex-stratified linear regression models were used to examine associations between baseline anxiety/depression and body composition change, then repeated controlling for baseline MVPA. Results: Overall, weight, BMI, fat mass, and subcutaneous adiposity significantly increased at year 2 (P<0.05). For women, a higher depression and anxiety score predicted increased weight, BMI, fat mass, and subcutaneous adiposity (P<0.05). Controlling for MVPA attenuated these associations to nonsignificance. For men, MVPA did not alter the associations between anxiety and increased weight, BMI, fat mass, and subcutaneous adiposity (P<0.05) or the associations between depression and decreased weight, BMI, fat mass, and subcutaneous adiposity (P<0.05). Conclusions: Anxiety and depression were related to body composition change for young adults. In women, MVPA attenuated these associations to nonsignificance. MVPA may buffer the adverse effects of depression and anxiety symptoms on young women's weight gain.