Overview
- A synthesis of 22 randomized trials involving 1,995 adults found no clinically meaningful weight-loss advantage for intermittent fasting over standard dietary advice or no program.
- Tested regimens included time-restricted eating, 5:2 periodic fasting, alternate-day fasting, and modified alternate-day fasting, with follow-up typically up to one year.
- Reviewers were moderately confident about the weight-loss conclusion, while evidence on other outcomes such as metabolic markers and quality of life was very uncertain.
- Key gaps included sparse reporting of patient-centered measures, with only one trial assessing quality of life and two reporting adverse events, and limited diversity across predominantly high-income, mostly White cohorts.
- Experts caution that social-media enthusiasm outpaces the evidence and recommend individualized, evidence-based strategies focused on whole foods and regular exercise, alongside calls for larger, longer, more diverse studies.