Impact of a preoperative low-calorie diet on liver histology in patients with fatty liver disease undergoing bariatric surgery

Abstract

BackgroundA low-calorie diet (LCD) before bariatric surgery has been shown to reduce liver volume and facilitate ease of operation. It is estimated that 75%–100% of individuals undergoing bariatric surgery have nonalcoholic fatty liver disease (NAFLD). ObjectivesWe aimed to investigate how an LCD affects liver histology in the setting of NAFLD. SettingUniversity Hospital, United States. MethodsForty intraoperative liver specimens were analyzed histologically as follows: 20 with and 20 without a preoperative 2-week, 1200 kcal/d LCD. Weight was measured prediet, at surgery, and 6 months after surgery. NAFLD activity score was used to grade liver histology at surgery. The NAFLD activity score scores steatosis, lobular inflammation, hepatocellular ballooning, and fibrosis. ResultsThe non-LCD group (n = 20) had mean weight at surgery of 136.1 ± 24.1 kg. The LCD group (n = 20) had initial mean weight of 128.6 ± 25.4 kg, with presurgical weight loss of 3.43 kg (range, 0–9.3 kg), mean change in body mass index 1.24 kg/m2 (2.66% total weight loss) on an LCD. The LCD group had significantly less steatosis (P = .02), fewer foci of lobular inflammation (P = .01), and less hepatocellular ballooning (P = .04) compared with the non-LCD group; with no difference in degree of fibrosis. Fewer patients in the LCD group had nonalcoholic steatohepatitis with ballooning (P = .04). Weight loss on an LCD before bariatric surgery was predictive of weight loss 6 months after surgery (P = .026). ConclusionsA 2-week LCD before bariatric surgery is associated with significant improvement in steatosis, inflammation, and hepatocellular ballooning in NAFLD. Among LCD patients, preoperative weight loss was associated with improved 6-month weight loss and liver function.