Abstract 075: Differences In Body Composition At Baseline And In Response To Exercise Training By Metabolic Health And Weight Status

Background: Body composition is known to differ across metabolic health and weight phenotypes. Regular exercise improves body composition, yet little is known about differences in exercise response across metabolic health and weight phenotypes. Methods: Normal weight (n=376) and overweight/obese (OWOB) adults (n=456) from the HERITAGE Family Study (56% female, 38% Black) completed a 20-week endurance training program. Four groups based on baseline BMI and metabolic risk were created: metabolically healthy normal weight, MHNW; metabolically unhealthy normal weight, MUNW; metabolically healthy OWOB, MHO; and metabolically unhealthy OWOB, MUO. Unhealthy was defined as having ≥2 metabolic syndrome components. General linear models tested for differences in baseline and change in measures of body composition (fat mass [FM], fat-free mass [FFM], % body fat [%BF], visceral fat) after adjusting for age, sex, and ethnicity (and baseline value in change models). Results: Table 1 shows adjusted mean baseline and change in body composition values by group. Baseline body composition tended to track with weight status, with NW adults having lower FM, %BF, and visceral fat compared to obese adults (p<0.05), regardless of metabolic health. However, the MHO group had lower baseline values of these traits compared to MUO (p<0.05). Body composition measures significantly improved with exercise training in all groups, however, the magnitude of change differed between groups. For example, both NW groups had larger decreases in %BF compared to the obese groups, with MUNW showing the largest decrease. Conversely, MHNW showed the largest decrease in visceral fat, which was greater than both obese groups, but change in visceral fat was similar between MHO and MUNW. Conclusions: Normal weight adults tended to have better body composition profiles at baseline and larger improvements with exercise compared to obese adults, regardless of metabolic health. Within weight groups, body composition improved regardless of metabolic health status.