EFFECTS OF LARGE EXERCISE-INDUCED WEIGHT LOSS ON ABDOMINAL FAT AND LIPID LEVELS IN OBESE MALES

Abstract

PURPOSE: This study examined whether reductions in abdominal fat following large exercise-induced weight loss were related to changes in lipid levels in obese Singaporean males, independent of changes in weight. METHODS: 20 obese males (mean age 19.8 ± 0.6yrs) were evaluated before (pre-training) and after (post-training) four months of regimented training in the Singapore Armed Forces. 30 obese males (mean age19.2 ± 1.3yrs) without training were monitored as control subjects. Fat free mass (FFM), fat mass (FM) and per cent (%) body fat were determined from skinfold measurements. Body mass index (BMI) and waist hip ratio (WHR) were calculated from height, weight and circumferences taken pre- and post-training using standard methods. Blood samples were collected after an overnight fast to determine plasma lipid levels. Differences between pre- and post-training responses were analyzed with a paired t-test. RESULTS: From pre- to post-training, there were decreases in waist circumference and hip circumference (P < 0.001), the decrease in WHR (P < 0.001) indicating a greater mobilization of upper body fat and a preferential loss of fat from this region. Exercise-induced weight loss (12kg) decreased CHD risk as indicated by the reductions in total cholesterol, LDL-C and Apo B (all P < 0.001). However, there was no evidence that the pre-training measures of WHR or waist circumference were related to the pre-training measures of these risk factors, nor were there any relations between the changes in WHR and waist circumference and the changes in lipid levels that accompanied exercise-induced weight loss. In contrast, pre-training levels of metabolic variables were inversely related to the subsequent chang in each of these measures. Thus, those with the higher levels of lipids prior to training experienced the gratest improvements following weight loss. CONCLUSION: These data suggest that exercise-induced weight loss is associated with a reduction in abdominal obesity in men, but that changes in fat distribution may not be related to changes in cardiovascular risk factors.Table: No Caption Available