Intermittent fasting “works”, or rather, it works more or less like other diets, but it is not miraculous. This is stated by a review of the scientific studies published to date on the subject. The review was completed by Cochrane, an international network famous for the evaluation of scientific research. The investigation brought together data from 22 randomized studies involving a total of 1,995 adults across Europe, North America, China, Australia and South America. The result the researchers reached is quite disappointing: “The evidence supporting intermittent fasting for weight loss falls short of expectations.”
What the review of studies says about intermittent fasting
The studies reviewed were all published between 2016 and 2024 and examined various modes of intermittent fasting: time-restricted feeding (which involves eating meals in a narrow window of time), periodic fasting, and alternate-day fasting.
Most studies followed participants for up to 12 months. On average, the subjects lost only 3% of their body weight through the various fasting modalities, well below the 5% that doctors consider to be a clinically significant percentage. “Intermittent fasting likely results in little or no difference in the rate of weight loss,” the review reads.
The benefits on quality of life compared to other diets are also very uncertain, especially since none of the research analyzed reports data on participant satisfaction. As for the reporting of side effects, “it was inconsistent across different studies”, we read in the article published on the Cochrane website, “making it difficult to draw definitive conclusions”.
“It’s not a silver bullet, but it can be an option”
“Intermittent fasting is not a silver bullet, but it can be one of many options for weight management,” commented Luis Garegnani, director of the Cochrane Associate Center at the Italian Hospital in Buenos Aires, and first author of the review. “Intermittent fasting probably produces similar results to traditional dietary approaches to weight loss. It doesn’t look dramatically better, but it’s not worse either.” The researchers highlight, however, that many of the studies examined have limitations as they were carried out with “small samples and inconsistent reporting”.
It is also pointed out that few studies “have examined long-term outcomes.” For these reasons it is “difficult to draw definitive conclusions”. In short, a sort of question mark remains, but Garegnani is quite sure that optimism about this type of diet is misplaced. “Intermittent fasting does not appear to work for overweight or obese adults trying to lose weight. It may be a reasonable option for some, but the current evidence does not justify the enthusiasm we see on social media.”