Effects of intermittent fasting regimens on glycemic, hepatic, anthropometric, and clinical markers in patients with non-alcoholic fatty liver disease: Systematic review and meta-analysis of randomized controlled trials

Intermittent fasting (IF) regimens have been hypothesized to influence several markers of cardiometabolic and liver function. The objective of our meta-analysis was to investigate the impact of IF regimens on cardiometabolic and liver markers in subjects diagnosed with non-alcoholic fatty liver disease (NAFLD). We searched several online databases (PubMed/Medline, Web of Science, Scopus and Embase) in order to identify suitable publications for inclusion in the meta-analysis. Results were expressed as weighted mean differences (WMD). From 12343 articles identified in different databases, a total of 7 RCT arms were entered into the quantitative synthesis. The manuscripts were published between 2019 and 2023. IF regimens (the 5:2 diet, 16/8 time-restricting feeding, and alternate day fasting) varied from 2 months to 3 months. IF regimens reduced steatosis scores (WMD: -33.22 CAP dB/m, 95 % CI: -50.72 to -15.72), anthropometric characteristics of obesity (WMD: -0.77 kg/m , 95 % CI: -1.38 to -0.17 for body mass index; WMD: -3.16 kg, 95 % CI: -4.71 to -1.61 for body weight; WMD: -1.90 kg, 95 % CI: -3.51 to -0.29 for waist circumference), as well as ALT (WMD: -9.10 U/L, 95 % CI: -12.45 to -5.75), triglyceride (WMD: -20.83 mg/dl, 95 % CI: -39.01 to -2.66), total cholesterol (WMD: -7.80 mg/dl, 95 % CI: -15.18), HbA1c (WMD: -0.14 %, 95 % CI: -0.20 to -0.08) and HOMA-IR (WMD: -1.21, 95 % CI: -2.08 to -0.34) levels versus controls. Nevertheless, no between-group differences were detected for other biomarkers, e.g., fasting blood glucose, insulin, AST, HDL-C or LDL-C values, and fibrosis scores. IF regimens can improve some markers of cardiometabolic and liver function in patients with NAFLD. However, the available evidence to support the benefits of IF regimens is limited and derived from a small number of studies, thus further research is needed to clarify the impact of IF on the cardiometabolic health of NAFLD patients.