Association of Perceived Weight Status and Change in Physical Activity in Young Adults

Abstract

PURPOSE: To investigate the longitudinal association between perceived weight status and physical activity (PA) change in a population based sample of young adults. METHODS: The sample consisted of 338 females and 290 males, aged 21–25 years (85% white). At baseline, subjects classified themselves as underweight (UW), normal weight (NW), slightly overweight (OW) and very overweight (VOW). PA (hrs/wk) averaged over the past year was assessed by questionnaire twice (mean time between assessments = 25.3±5.9 months) and change in PA between the two assessments was calculated. Analysis of covariance was used to examine the relation between baseline perceived weight status and change in PA, while adjusting for demographic characteristics. RESULTS: Perception of weight status at baseline for females was 7%-UW, 40%-NW, 40%-OW and 13%-VOW; and for males 15%-UW, 51%-NW, 30%-OW, and 4% -VOW. Overall, PA decreased by −1.2±7.3 hrs/wk with PA in males decreasing significantly more than in females (−0.3±6.6 vs. −2.1±7.9, p < 0.01). Baseline perceived weight status was a significant predictor of change in PA for both males (p <.01) and females (p <0.05). Analysis of covariance indicated that females who perceived their weight status to be OW or VOW significantly increased their PA by 0.2 and 1.7 hrs/wk respectively while females who perceived their weight status to be UW or NW decreased their PA by −1.2 and −1.4 hrs/wk respectively. Among males, those who perceived their weight status to be VO significantly increased their PA by 2.6 hrs/wk while males who perceived their weight status as UW, NW or OW decreased their PA by −4.7, −2.5 and −1.1 hrs/wk respectively. CONCLUSION: These data indicate that perception of weight status may be a predictor of change in physical activity. Over a 2 year period, PA decreased in those who perceived they were under or normal weight while PA increased among those who perceived they were overweight.