Intermittent fasting has become one of the most popular weight-loss trends in recent years, promoted widely on social media and by lifestyle influencers.
But a major new review suggests the results may not live up to the hype, especially for people who are overweight or obese.
Researchers analyzing evidence for the Cochrane Database of Systematic Reviews found that intermittent fasting does not lead to significantly greater weight loss than traditional diet advice—or even no structured intervention at all.
The findings raise questions about whether fasting plans offer real advantages over more conventional approaches.
Obesity remains a major global health challenge. According to the World Health Organization, adult obesity has more than tripled since 1975. In 2022 alone, about 2.5 billion adults worldwide were overweight, including 890 million living with obesity.
Because excess weight increases the risk of heart disease, diabetes, and other serious conditions, effective weight-loss strategies are urgently needed.
To evaluate intermittent fasting, researchers reviewed 22 randomized clinical trials involving nearly 2,000 adults from North America, Europe, China, Australia, and South America.
The studies examined several types of fasting plans, including alternate-day fasting, periodic fasting, and time-restricted eating, where people limit food intake to certain hours of the day. Most trials tracked participants for up to one year.
When compared with standard dietary advice, intermittent fasting did not produce a meaningful difference in weight loss. Results were also similar when compared with people who received no specific weight-loss guidance. The researchers concluded that fasting schedules alone may not be more effective than simply following general healthy eating recommendations.
The review also noted that reports of side effects varied widely between studies, making it difficult to assess safety. Many trials were small or short-term, which limits confidence in the results. Because obesity is a long-term condition, experts say longer studies are needed to understand whether fasting could provide benefits over time.
Researchers caution that intermittent fasting may still work for some individuals, depending on personal preferences, lifestyle, and health conditions. However, current evidence does not support the widespread enthusiasm seen online. Doctors are encouraged to consider each patient’s situation individually rather than recommending fasting as a universal solution.
Another limitation is that most studies involved participants from high-income countries, often with similar backgrounds. Obesity rates are rising rapidly in lower-income regions as well, and future research will need to include more diverse populations to determine whether results differ across cultures and lifestyles.
Experts emphasize that sustainable weight loss usually requires a combination of balanced nutrition, physical activity, adequate sleep, and long-term behavioral changes. While intermittent fasting can be one possible approach, it is not a guaranteed shortcut.
In the end, the review suggests that there is no single diet that works for everyone. Instead of chasing trends, individuals may benefit more from finding healthy habits they can maintain over the long term.
