Intermittent fasting might be trendy—but the evidence suggests it’s no magic bullet for weight loss.
Intermittent fasting may not deliver greater weight loss than standard diet advice or even no specific diet plan at all, according to a new Cochrane review. The findings challenge the widespread belief that fasting schedules offer a unique advantage for people who are overweight or living with obesity.
Obesity Remains a Global Health Crisis
Obesity continues to pose a serious public health threat and is now one of the leading causes of death in high-income countries. The World Health Organization reports that global adult obesity rates have more than tripled since 1975. In 2022, an estimated 2.5 billion adults were overweight, including 890 million who were living with obesity.
Despite this growing crisis, intermittent fasting has become increasingly popular. Social media platforms, wellness influencers, and bold claims about rapid weight loss and metabolic improvements have fueled enthusiasm for eating patterns such as alternate-day fasting and time-restricted feeding.
Large Review Finds No Clear Weight Loss Advantage
To better understand whether intermittent fasting truly stands out, researchers reviewed 22 randomized clinical trials that included 1,995 adults from North America, Europe, China, Australia, and South America. The studies examined several approaches, including alternate-day fasting, periodic fasting, and time-restricted feeding. Most participants were followed for up to one year.
When compared with traditional dietary advice or no intervention, intermittent fasting did not produce a clinically meaningful difference in weight loss. In other words, fasting schedules did not outperform standard approaches.
The researchers also noted that reporting on side effects varied widely from study to study. Because many trials were small and data collection was inconsistent, drawing firm conclusions about safety and long-term effects remains difficult. Overall, the available evidence is still limited.
“Intermittent fasting just doesn’t seem to work for overweight or obese adults trying to lose weight,” said Luis Garegnani, lead author of the review from the Universidad Hospital Italiano de Buenos Aires Cochrane Associate Centre.
Online Hype vs Scientific Evidence
Garegnani urged caution about the excitement surrounding fasting on social media. “Intermittent fasting may be a reasonable option for some people, but the current evidence doesn’t justify the enthusiasm we see on social media.”
Another limitation is the lack of long-term research. Few studies have tracked outcomes beyond short trial periods. “Obesity is a chronic condition. Short-term trials make it difficult to guide long-term decision-making for patients and clinicians,” Garegnani added.
Most of the studies included primarily white participants living in high-income countries. Given that obesity is rising rapidly in low and middle-income nations, the findings may not fully apply to those populations. The authors stress that results could differ depending on sex, age, ethnic background, health conditions, or existing eating behaviors and disorders.
“With the current evidence available, it’s hard to make a general recommendation,” said Eva Madrid, senior author from Cochrane Evidence Synthesis Unit Iberoamerica. “Doctors will need to take a case-by-case approach when advising an overweight adult on losing weight.”
Reference: “Intermittent fasting for adults with overweight or obesity”by Luis I Garegnani, Gisela Oltra, Diego Ivaldi, Mariana Andrea Burgos, Paola J Andrenacci, Sabrina Rico, Melinda Boyd, Diane Radler, Camila Micaela Escobar Liquitay and Eva Madrid, 16 February 2026, Cochrane Database of Systematic Reviews.
DOI: 10.1002/14651858.CD015610.pub2
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1 Comment
It worked for me. I lost over 30 lbs. I was only eating from about 4 PM or later to about 3 AM (I have weird sleeping hours) and I’d sleep from around 3 or 4 AM to 11 AM or noonish. I’d get up and not really eat anything until the late afternoon or evening. Sometimes I wouldn’t eat anything substantial until 8 or 9 PM. I just wasn’t really hungry during the daytime. I hadn’t even planned to do intermittent fasting. I just kind of fell into it. Next thing I knew I was losing weight like crazy so I leaned into it.
I guess some people just eat too much during the hours that they are supposed to be eating. It is possible to overeat while doing intermittent fasting. I overall ate less. Basically one full meal at what is normally dinner time and then a snack/meal before going to bed. And a few snacks to take my various prescriptions and vitamins with during the day. If people are still eating three full meals and snacks during those hours when they are supposed to be eating, they are not reducing their calories so they are not going to lose weight. I think the idea that the timing of it is what causes the weight loss is wrong. It’s simply eating less that will work.