The effect of a low-carbohydrate diet on the nonalcoholic fatty liver in morbidly obese patients before bariatric surgery

Background: Bariatric surgery may be complicated by enlargement of the liver, especially of the left lobe, caused by nonalcoholic fatty liver disease often present with morbid obesity. Methods: The effect of a very low carbohydrate diet for 4 weeks before surgery on liver density and volume was assessed in 14 candidates for bariatric surgery. Computed tomography (CT) scans were performed before and at termination of the diet period. Results: The CT scans clearly showed a significant increase in mean liver density (p = 0.06) and a decrease in mean liver volume (p = 0.01). The increased mean density of the left lobe was markedly greater than that of the right lobe. Conclusions: The findings show that 4 weeks of a very low carbohydrate diet reduces liver fat content and liver size, particularly of the left lobe. This approach may render bariatric surgery or any foregut operations less difficult in morbidly obese patients and may be a useful treatment for nonalcoholic fatty liver disease.