Changes in Abdominal Adipose Tissue Compartments with Changes in Body Weight

Abstract

The use of imaging techniques such as computed tomography (CT) allows for the subdivision of abdominal subcutaneous adipose tissue (SAT) and may aid in the determination of the relative importance of specific adipose tissue (AT) depots to metabolic health, specifically insulin resistance (IR). PURPOSE: The purpose of this study was to investigate the effects of a diet- and exercise-induced weight loss intervention on abdominal AT distribution and IR in overweight and inactive individuals with characteristics of the metabolic syndrome. METHODS: Twenty-five sedentary and overweight to class II obese [body mass index (BMI) = 33.0 ± 0.8 kg/m2] individuals (8 males, and 17 females, age = 40 ± 2 y), completed a 4–7 mo diet- and exercise-induced weight loss intervention with a target body weight reduction of 10%. The diet consisted of modest energy restriction (∼ 600 kcal/d) and subjects performed 45 minutes of cardiovascular exercise 5 d/wk at 60% of VO2max, expending approximately 375 kcal/session. Basal, fasting serum glucose and insulin concentrations were used to determine IR by the homeostasis model assessment (HOMA). Abdominal AT depots were measured using CT. Blood samples and CT scans were collected at baseline and post weight loss. RESULTS: Following weight loss (9.3 ± 0.3%; mean ± SE), all abdominal adipose tissue depots [total AT (TAT), total SAT (TSAT), superficial SAT (sSAT), deep SAT (dSAT), and visceral AT (VAT)] were significantly reduced (p<0.01). Body weight, BMI, % body fat, and waist circumference also were significantly reduced (p<0.01). VAT was preferentially reduced (23.9%) vs. TAT (17.7%), TSAT (15.4%), sSAT (14.3%), and dSAT (16.1%). No abdominal AT depots were significantly correlated with HOMA at baseline; however, post weight loss VAT was significantly correlated with post weight loss HOMA (r = .562, p<0.01). The change score (difference from baseline to post weight loss) in VAT also was significantly correlated to the change score for HOMA (r = .429, p<0.05). CONCLUSIONS: Weight loss resulted in favorable changes in all abdominal AT depots with a preferential reduction in VAT. The overall change in VAT was most closely related to the change in IR. Diet- and exercise-induced weight loss represents a means by which to reduce abdominal adiposity and metabolic risk. Supported by NIH ROIDK67036