Overview
- Researchers synthesized 22 randomized trials involving 1,995 adults with overweight or obesity, tracking results for up to 12 months.
- When compared with conventional energy-restricted plans, intermittent-fasting protocols produced similar weight loss with no meaningful advantage.
- Against no‑diet controls, fasting groups lost roughly 3% to 3.5% of body weight on average, below the ~5% threshold often considered clinically meaningful.
- The evidence base remains limited by small samples, short durations, inconsistent reporting, and overrepresentation of white participants in high‑income countries, with varied fasting methods studied.
- Experts say fasting may still suit personal preference for some individuals, while calling for longer, larger, and more diverse trials that evaluate metabolic outcomes, adherence, lean‑mass changes, and potential harms.