Rapid significant weight loss and regional lipid deposition: Implications for insulin sensitivity.

Aim: To compare regional lipid deposition and insulin sensitivity after differing weight loss strategies: very low calorie diet (VLCD) and laparoscopic adjustable gastric banding (LAGB).

Method: Thirty-nine obese women underwent anthropometry, proton magnetic resonance (MR) spectroscopy for assessment of liver fat (LFAT) and MR imaging for visceral (VAT) and subcutaneous abdominal fat volume (SAT) determination. Fasting blood was taken for insulin, glucose and free fatty acid (FFA) analysis. Measurements were repeated after 6-weeks Optifast VLCD (n = 14) or 3 months after LAGB (n = 25).

Results: Similar, significant (p < 0.001) weight loss occurred after VLCD (8%) and LAGB (9%). Both interventions induced significant (p < 0.001) and similar reductions in body mass index (BMI) and waist circumference, and in SAT and VAT (VLCD p < 0.05, LAGB p < 0.001). LFAT fell only after VLCD (p < 0.05). Plasma FFA only fell after LAGB (p < 0.05). Homeostasis model assessment (HOMA-R) improved only following VLCD (p < 0.05). No relations were detected between the changes in LFAT, VAT and SAT. The change in LFAT related to the change in HOMA-R in both interventions combined (r = 0.410, p = 0.013) and in the VLCD group (r = 0.660, p = 0.020). There was no change in relative dietary fat intake after LAGB (p = 0.11).

Conclusion: Caloric and fat restriction for 6 weeks (VLCD) reduces weight, SAT, VAT, LFAT and HOMA-R. Less severe caloric restriction for 12 weeks (LAGB) causes significant loss of weight, VAT and SAT but no detectable change in LFAT and HOMA-R. Following weight loss, a change in LFAT is related more to changes in insulin sensitivity or dietary fat than to abdominal adiposity loss.