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

Risa M. Wolf, Kiyoko Oshima, Joseph K. Canner, Kimberley Steele

Research output: Contribution to journalArticlepeer-review


Background: A 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). Objectives: We aimed to investigate how an LCD affects liver histology in the setting of NAFLD. Setting: University Hospital, United States. Methods: Forty 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. Results: The 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). Conclusions: A 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.

Original languageEnglish (US)
Pages (from-to)1766-1772
Number of pages7
JournalSurgery for Obesity and Related Diseases
Issue number10
StatePublished - Oct 2019


  • Bariatric surgery
  • Liver histology
  • Low-calorie diet
  • Nonalcoholic steatohepatitis
  • Preoperative weight loss

ASJC Scopus subject areas

  • Surgery


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