Effect of moderate weight loss on hepatic, pancreatic and visceral lipids in obese subjects

OBJECTIVE: To compare the effects of weight loss on visceral and subcutaneous abdominal fat, liver and pancreas lipid contentand to test the effects of these changes on metabolic improvement observed after weight loss.DESIGN: Weight-loss program designed to achieve a loss of 7--10% of the initial weight.SUBJECTS: 24 obese subjects (13 males and 11 females) with age ranging from 26 to 69 years and body mass index (BMI)30.2 -- 50.5 kgm2. Measurements: weight, BMI, waist circumference, body composition as assessed by dual-energy X-rayabsorptiometry, metabolic variables, leptin, adiponectin, visceral and subcutaneous abdominal fat, liver and pancreas lipidcontent as assessed by magnetic resonance were evaluated before and after weight loss achieved by hypocaloric diet.RESULTS: After a mean body weight decrease of 8.9%, BMI, waist circumference, fat mass, all metabolic variables, homeostasismodel assessment of insulin resistance (HOMA), alanine amino transferase, gamma glutamyl transpeptidase, high-sensitivityC-reactive protein (hs-CRP) and leptin, but not adiponectin and high-density lipoprotein-cholesterol, significantly decreased (allPo0.01). Visceral and subcutaneos abdominal fat, liver and pancreas lipid content significantly decreased (all Po0.01). Percentchanges in liver lipid content were greater (84.1±3%) than those in lipid pancreas content (42.3±29%) and visceral abdominalfat (31.9±15.6%). After weight loss, percentage of subjects with liver steatosis decreased from 75 to 12.5%. Insulin resistanceimprovement was predicted by changes in liver lipid content independently of changes in visceral fat, pancreas lipid content,systemic inflammation, leptin and gender.CONCLUSION: Moderate weight loss determines significant decline in visceral abdominal fat, lipid content in liver andpancreas. Reduction of liver lipid content was greater than that of pancreas lipid content and visceral fat loss. Liver lipidcontent is the strongest predictor of insulin resistance improvement after weight loss.