Effects of Weight Loss on Abdominal Fat Stores in Overweight and Obese Subjects

Abstract

Obesity affects 67% of the American population, increasing the risk for hyperlipidemia, hyperglycemia, hypertension, diabetes, and stroke. Visceral adipose tissue of the abdomen has been linked to an increased risk of these comorbidities. PURPOSE: To determine changes in visceral and subcutaneous adipose tissue of the abdomen, body mass, and BMI in men and women following an 8-week community weight loss program. METHODS: Forty subjects, twenty-nine females and eleven males (mean + SD, age: 55 + 12 y; height: 1.7 +.08 m; body mass: 106.0 + 23.8 kg; body mass index: 37.0 + 7.1 kg/m2) participated in an 8-week community weight loss study consisting of a low-calorie diet (1200 kcal/day) and moderate physical activity. Subjects maintained daily dietary and exercise logs throughout the 8-week program. Subjects participated in weekly group meetings where they received education and applied behavioral strategies related to the food exchange system, and exercise adherence. Two test periods (pre- and post-test) were analyzed using paired sample T-tests to determine changes in body mass, BMI, visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT). Total adipose tissue, SAT, and VAT were estimated using anthropometric sagittal diameter and predictive equations. Self-reported data was used to monitor adherence to diet and exercise. RESULTS: Significant differences (p<0.01) from pre-test to post-test were found for body mass, BMI, VAT and SAT. Reductions in abdominal adipose tissue were 15% for VAT and 9.6% for SAT after 8 weeks of intervention. Dietary adherence rates of 60-100% were reported from 77% of subjects while exercise adherence rates of 60-100% were reported from 64% of subjects. Average attendance rate was 92% over 8 weeks. CONCLUSION: A significant (p<0.01) decrease in body mass led to significant losses (p< 0.01) in visceral and subcutaneous adipose tissue. Post-test data showed a greater relative loss of abdominal VAT than abdominal SAT. These results are important when considering other studies that have identified an association between visceral adipose tissue and obesity-related co-morbidities.