The Effect of a Ketogenic Diet on Liver Health: A Systematic Review and Meta-Analysis Publisher Pubmed



Qu Y ; Sohouli M H ; Rohani P ; Cerqueira H S ; Gomes G K ; Santos H O
Source: Nutrition Reviews Published:2026

Abstract

Context: In the absence of long-term research with respect to the impact of a ketogenic diet (KD) on liver disease progression, further investigation into the screening for liver enzymes is useful in attempting to elucidate whether a KD may result in positive or negative effects. Objective: The goal of this study was to thoroughly examine how a KD affects liver health. Data Sources: The PubMed/Medline, Web of Science, Scopus, Cochrane Library, and Embase databases were searched to find pertinent randomized controlled trials (RCTs). Data Extraction: This systematic review featured 20 RCTs investigating the impact of a KD on liver enzymes and liver stiffness. A random-effects model analysis was undertaken, yielding pooled weighted mean differences and 95% CIs. Data Analysis: A quantitative meta-analysis showed that a KD has a significant lowering effect on levels of aspartate aminotransferase (AST) [weighted mean difference (WMD): −3.56 U/L; 95% CI: −6.61, −0.51], alanine aminotransferase (ALT) (WMD: −3.03 U/L; 95% CI: −5.26, −0.81), gamma-glutamyl transferase (GGT) (WMD: −12.25 U/L; 95% CI: −22.08, −2.42), and alkaline phosphatase (ALP) (WMD: −5.29 U/L; 95% CI: −9.85 to −0.74). However, the findings obtained from the meta-analysis showed that a KD has no significant effect on liver fibrosis (liver stiffness) (WMD: 0.40; 95% CI: −0.23, 1.04). The findings also showed that a KD followed for a duration of less than 12 weeks caused greater reductions in liver enzymes, including AST, ALT, and GGT, in people with a BMI of less than 30. Conclusions: In general, KDs can reduce traditional liver enzyme levels (ALT, AST, ALP, and GGT), but they appear to have no significant effect on liver stiffness. © The Author(s) 2025. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/pages/standard-publication-reuse-rights)