Written by Peter Liu
Spoon Feed
Two RCTs on intermittent fasting (IF) found greater weight loss in patients with obesity and greater reduction in liver fat content.
Intermittent fasting drops weight fast
Intermittent fasting (IF) has emerged as an effective dieting and weight loss strategy. Three subtypes of IF include alternate-day fasting (ADF), the 5:2 diet (fasting two days weekly), and time-restricted eating (TRE; where parts of a 24-hour day are designated for eating and fasting). These fasting methods are at least as effective as other weight-loss methods, such as caloric restriction. Two studies of IF are featured today.
The first evaluated the effects of IF on liver fat content. Seventy-two patients with metabolic dysfunction-associated steatotic liver disease (MASLD) and without diabetes were randomized to a 5:2 IF or caloric restriction. After 12 weeks, more patients in the 5:2 diet group had a ≥30% reduction in liver fat content compared to caloric restriction alone (72.2% vs 44.4%, p=0.03). These findings were most significant in patients with obesity, and patients with obesity also exhibited greater weight loss (-5.5% vs. -2.9%; P = .039). Changes in fibrosis, body composition, and liver enzymes were non-significant (all P > .05).
In the second study, 197 patients with obesity were randomized to early, late, or self-selected time-restricted eating (TRE), or to usual care with Mediterranean diet education, evaluating diet effects on visceral adipose tissue (VAT) quantified by MRI. No significant differences in VAT reduction were observed between the TRE groups and usual care (all p ≥ 0.31). TRE groups showed greater weight loss (−2.4 to −3.1 kg; p < 0.004) but no additional cardiometabolic benefits beyond usual care.
Overall, these studies add to the growing body of evidence that IF techniques are effective at weight loss and may have small benefits in some metabolic measures as well, such as liver fat content.
How does this change my practice?
I have not recommended IF to my patients. However, in patients who are receptive to IF, particularly those with obesity and MASLD who have been otherwise optimized, there is now some small RCT-level evidence that supports it, and I suspect I will start suggesting this.
Sources
Effects of Intermittent Calorie Restriction in Nondiabetic Patients With Metabolic Dysfunction-Associated Steatotic Liver Disease. Clin Gastroenterol Hepatol. 2025 Jan;23(1):114-123.e13. doi: 10.1016/j.cgh.2024.06.051. Epub 2024 Aug 23. PMID: 3918142
Effects of early, late and self-selected time-restricted eating on visceral adipose tissue and cardiometabolic health in participants with overweight or obesity: a randomized controlled trial. Nat Med. 2025 Feb;31(2):524-533. doi: 10.1038/s41591-024-03375-y. Epub 2025 Jan 7. PMID: 39775037
