Summary
A recent trial published in the Annals of Internal Medicine compared weight loss outcomes from intermittent fasting (IMF) and daily caloric restriction (DCR) in 165 adults without significant comorbidities.
Participants in the 12-month randomized control trial followed a weight-loss program that aimed for a 34.3% weekly energy deficit and received guidance on portion control, healthy eating, and calorie counting. The IMF arm applied an 80% caloric restriction for 3 days each week, with ad libitum intake on the other 4 days (4:3). The DCR arm maintained a constant daily caloric deficit.
At 12 months, participants following IMF lost significantly more weight than those in the DCR group (-7.7 kg vs. -4.8 kg; p = 0.04). Additionally, IMF participants had higher rates of achieving ≥ 5% and ≥ 10% weight loss. Adherence to the IMF regimen was higher at both 6 and 12 months and was well-tolerated.
The generalizability of these results is limited due to the low representation of males (26%) and Black (6%) individuals, the exclusion of older adults and individuals with diabetes or cardiovascular disease, and reliance on a high-intensity intervention that may not be widely accessible.
Sources
Catenacci VA, Ostendorf DM, Pan Z, et al. The effect of 4:3 intermittent fasting on weight loss at 12 months : a randomized clinical trial. Ann Intern Med. 2025;178(5):634-644. doi:10.7326/ANNALS-24-01631.
This summary was created with assistance from generative artificial intelligence (Microsoft CoPilot, 2025)
Featured Authors
Colin Crowe, MD
Case Western Reserve University