Intermittent fasting no better for weight loss than standard diets, review finds

Intermittent fasting shows no weight loss advantage

Intermittent fasting does not help overweight or obese adults lose more weight than standard diet advice or no program at all, according to a new Cochrane review. The analysis of 22 clinical trials challenges the popular belief that *when* you eat is more important for weight loss than traditional calorie-focused approaches.

Review finds no meaningful difference

Researchers examined data from 22 randomized clinical trials involving 1,995 adults across multiple continents. The studies tested methods like alternate-day fasting and time-restricted eating, with most following participants for up to a year.

Compared to conventional diet guidance or no intervention, intermittent fasting did not produce a clinically meaningful difference in weight loss. The fasting schedules simply did not outperform more traditional advice or doing nothing specific.

• Trials tested alternate-day fasting, periodic fasting, and time-restricted feeding.
• Most studies lasted 3 to 12 months.
• The evidence base is limited, with only 22 trials available.

Evidence lags behind social media hype

Lead author Luis Garegnani from the Universidad Hospital Italiano de Buenos Aires said the data doesn't support the online enthusiasm. "Intermittent fasting just doesn't seem to work for overweight or obese adults trying to lose weight," Garegnani stated.

He cautioned that intermittent fasting may be reasonable for some individuals, but the current evidence doesn't justify the widespread social media claims. The review also found that side effects were not consistently reported across studies, making full risk assessment difficult.

Lack of long-term data is a major concern

Few studies have examined how well intermittent fasting works over extended periods, which is problematic for managing a chronic condition like obesity. "Short-term trials make it difficult to guide long-term decision-making for patients and clinicians," Garegnani added.

Another limitation is that most trials included primarily white participants from high-income countries. Obesity is increasing rapidly in low and middle-income nations, where more research is needed.

Doctors need case-by-case approach

The authors emphasize that findings may not apply equally to everyone. Results could differ based on sex, age, ethnic background, or existing medical conditions.

"With the current evidence available, it's hard to make a general recommendation," said senior author Eva Madrid from Cochrane Evidence Synthesis Unit Iberoamerica. She concluded that doctors will need to take an individualized approach when advising overweight adults on weight loss strategies.