Intermittent fasting, a dietary trend that has swept through nutrition circles and social media feeds alike, is now facing a sobering reality check. According to a comprehensive Cochrane systematic review published on February 16, 2026, intermittent fasting appears to offer little to no advantage over standard dietary advice—or even doing nothing at all—when it comes to weight loss and quality of life for adults who are overweight or obese.
The review, as reported by BBC and the Cochrane Collaboration, analyzed 22 randomized controlled trials conducted between 2016 and 2024, spanning across North America, Europe, China, Australia, South America, and Brazil. Nearly 2,000 participants (1,995 to be exact) were enrolled in these outpatient studies, all classified as overweight or obese based on their body mass index (BMI). The research scrutinized several popular intermittent fasting strategies, including time-restricted eating (like the 16:8 diet), alternate-day fasting, and periodic fasting such as the 5:2 diet.
But what did the scientists actually find? In short, intermittent fasting did not outperform traditional dietary advice—such as calorie restriction or structured eating plans—when it came to shedding pounds. According to the review, the mean difference in weight loss between intermittent fasting and regular dietary advice was a mere -0.33% from baseline body weight, based on pooled data from 21 studies with 1,430 participants. For those hoping to achieve a more significant milestone, such as losing at least 5% of their starting body weight, the results were similarly underwhelming: four studies with 472 participants showed near-equivalent rates between those following intermittent fasting and those receiving regular dietary advice.
Lead review author Luis Garegnani, from the Universidad Hospital Italiano de Buenos Aires, expressed concern over the public excitement surrounding fasting. "Intermittent fasting may be a reasonable option for some people, but the current evidence doesn't justify the enthusiasm we see on social media," he told BBC. Senior review author Eva Madrid echoed this sentiment, emphasizing the need for a personalized approach: "Doctors will need to take a case-by-case approach when advising an overweight adult on losing weight."
The review also compared intermittent fasting to doing nothing at all—no dietary advice, no intervention, just business as usual. Here, too, the results were modest. Intermittent fasting led to about 5% weight loss, while the control groups lost around 2% of their original weight. However, as noted by The Conversation, a 3% difference in weight loss is not considered clinically meaningful in the medical community. The authors even suggested that some of the observed effects could be due to the Hawthorne effect, where people change their behavior simply because they know they're being studied.
Quality of life, another important measure for anyone embarking on a weight-loss journey, was also assessed. Using validated tools like the Assessment of Quality of Life-8D, SF-36, and RAND-36 surveys, the review found little to no difference between intermittent fasting and conventional dietary approaches. This finding was based on three studies with 106 participants, further reinforcing the message that fasting may not offer the transformative benefits some have hoped for.
So, what about safety? The review found that intermittent fasting may result in little to no difference in adverse events compared to regular dietary advice, though the evidence was rated as very uncertain. Reported side effects included nausea, headache, dizziness, hunger, constipation, diarrhea, dyspepsia, cold intolerance, irritability, insomnia, and impaired concentration. Subgroup analyses suggested that modified alternate-day fasting and alternate-day fasting might carry higher rates of adverse events compared to time-restricted feeding. Interestingly, studies from high-income countries showed increased adverse events with intermittent fasting, while a single study from a low- or middle-income country suggested fewer problems—though the authors cautioned that these findings are limited by the small number of studies in each subgroup.
Despite the lackluster results for weight loss, intermittent fasting is not without its proponents or potential benefits. Some studies, as highlighted by The Conversation, have found that intermittent fasting can lower blood pressure, improve fertility, and reduce the incidence of metabolic syndrome—a cluster of conditions that increase the risk of cardiovascular disease. There is also emerging evidence from recent studies suggesting that intermittent fasting may influence metabolism and gut health, and even restrict how cancer develops or improve the metabolic health of shift workers. However, these potential benefits were not the main focus of the Cochrane review, and more research is needed to fully understand their implications.
Experts outside the review have weighed in on the findings, too. Dr. Baptiste Leurent, an associate professor in medical statistics at University College London, remarked to BBC, "Taken together, the individual studies provide a clear indication that intermittent fasting offers little benefit. This is yet another example of a misalignment between public perception and the scientific evidence." Professor Keith Frayn, emeritus professor of human metabolism at the University of Oxford, added that claims about fasting's "special effects on metabolism" have little relevance, saying, "There are no 'quick fixes' for those who are overweight or obese beyond reducing calorie intake."
The review did not address participant satisfaction, diabetes status, or overall measures of comorbidity—important gaps that future studies will need to fill. Moreover, most included studies focused on short-term outcomes, with interventions lasting up to 12 months, and the vast majority were conducted in high-income countries. There was also a gender imbalance: seven studies were predominantly women, and only one was predominantly men, making it challenging to draw conclusions about sex-specific effects.
It's also worth noting that intermittent fasting is just one of several tools in the weight management toolbox. Other approaches, like very low-energy "shake" diets, GLP-1 medications, and bariatric surgery, have been shown to produce more substantial weight loss—sometimes far exceeding the modest results seen with fasting. For example, GLP-1 medications can result in 15% to 20% weight loss, while surgery can lead to more than 20%.
Meanwhile, the landscape of weight loss is rapidly evolving. In the UK alone, around 1.6 million adults are thought to be using weight loss injections such as Wegovy and Mounjaro, often obtained through private prescriptions. However, a recent study found that people who stop using these medications regain weight four times faster than those who stop conventional dieting and exercising, highlighting the challenges of maintaining weight loss over the long term.
Ultimately, the authors of the Cochrane review advise caution and practicality. "Physicians and patients may need to evaluate willingness and readiness to implement intermittent fasting as a treatment strategy, based on individual practicality and sustainability," they wrote. As the science stands, intermittent fasting may be safe and suitable for some, but it's far from a miracle cure. For now, the best advice remains to find a weight management strategy that fits your lifestyle, preferences, and health needs—and to consult a healthcare professional before making any major changes.
As the search for effective, sustainable weight loss solutions continues, one thing is clear: there are no shortcuts, and the evidence behind the latest fads should always be weighed carefully.