Changes in Body Fat Phenotype After Four-Month Walking Interventions

Abstract

Walking is an excellent health-promoting activity for obese, sedentary individuals. Visceral fat is linked to cardiovascular disease and mortality. We hypothesized that walking (steps/day) would decrease visceral adiposity and improve laboratory markers of cardiometabolic health in a dose-dependent manner. In the primary study, 79 sedentary, overweight subjects (77% female, 65% Caucasian) were enrolled in a 2x2 factorial randomized controlled walking intervention, with steps measured using a wearable Fitbit fitness tracking device. Participants underwent dual x-ray energy absorptiometry and basic cardiometabolic laboratory measurements (glucose, insulin, total cholesterol, HDL, LDL, triglycerides) before and after the intervention. Lean mass increased from 49.9 ± 9.5 to 50.3 ± 9.4 (p=0.05). No significant changes were observed in any of the cardiometabolic outcomes or localization of fat. The change in steps had no correlation with weight, visceral fat, lean mass, and VO2 peak, refuting the original hypothesis. When analyzing common laboratory markers and demographic characteristics, there were no significant predictors for visceral or total fat mass change, with significant heterogeneity of change in the group. Our study supports the likely contribution of genetic and environmental factors to the physical and laboratory changes seen following a walking intervention in sedentary and insufficiently active overweight people.