Background: Laparoscopic adjustable gastric banding (LAGB) requires surgical access to the gastroesophageal junction, which may be compromised by the enlarged, fatty liver that is frequently encountered in the obese. Liver size appears reduced and surgical access improved following preoperative weight loss with Optifast^® Very Low Calorie Diet (VLCD). The aim of this study was to assess the effects of 6 weeks Optifast^® VLCD on liver volume and fat content. Methods: 18 morbidly obese subjects underwent magnetic resonance imaging and spectroscopy to measure liver size and fat content before and after intensive treatment with Optifast^® VLCD for 6 weeks. Results: All subjects completing 6 weeks Optifast^® VLCD lost weight. Body weight and BMI (median [interquartile range]) reduced from 119.7 [111.9-131.3] kg and 44 [40-51] kg/m² respectively, to 110.6 [98.0124.5] kg and 40 [36-47] kg/m², P<0.001. Median excess weight loss (EWL) was 15.1 [9.6-21.1]%. Baseline liver volume and fat content were related (r=0.633, P=0.005). After 6 weeks Optifast^® VLCD, there was a 14.7% reduction in mean liver volume (P<0.001) and a 43% reduction in mean liver fat (P=0.016). The change in liver volume was predicted by the change in the liver fat (r = 0.610, P=0.012). Conclusion: This study has demonstrated that a 6week diet with Optifast^® VLCD results in significant related reductions in liver size and liver fat content. This suggests that the reduction in liver volume is due to loss of fat. The reduction in liver fat and volume likely accounts for the perceived improved operability in patients undergoing LAGB.