Intermittent fasting may be no better than 'doing nothing,' major review finds

One of the most popular weight-loss trends of the past decade might not deliver better results than traditional dieting, a major new review found.

A Cochrane analysis of 22 randomized clinical trials involving nearly 2,000 adults across North America, Europe, China, Australia and South America found that intermittent fasting resulted in "little to no difference" in weight loss compared to standard dietary advice. 

The results were barely more effective than "doing nothing," according to the researchers.

"Intermittent fasting just doesn't seem to work for overweight or obese adults trying to lose weight," lead researcher Luis Garegnani, Ph.D., director of the Universidad Hospital Italiano de Buenos Aires Cochrane Associate Center, said in a statement. 

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"It may be a reasonable option for some people, but the current evidence doesn't justify the enthusiasm we see on social media."

Intermittent fasting has surged in popularity on social media, often promoted as an easy shortcut to fat loss, metabolic health and even longevity. 

But as obesity rates climb worldwide — more than 2.5 billion adults were overweight in 2022, including 890 million with obesity, according to the World Health Organization (WHO) — weight-loss strategies are under intense scrutiny.

The review examined several forms of intermittent fasting, an eating pattern that alternates between set periods of eating and fasting, such as limiting meals to an eight-hour daily window or fasting every other day. Most of the studies followed participants for up to 12 months.

The review found the eating pattern did not produce clinically meaningful weight loss compared with traditional diets or no intervention, did not significantly increase the likelihood of losing at least 5% of body weight and showed no meaningful difference in quality of life.

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The review, however, had several limitations that made it difficult to assess long-term sustainability or apply the findings broadly, according to the researchers. 

Most of the studies lasted 12 months or less; none reported on participant satisfaction, diabetes outcomes or overall comorbidities; and most participants were White adults from high-income countries.

"With the current evidence available, it's hard to make a general recommendation," Dr. Eva Madrid, director of the Cochrane Evidence Synthesis Unit Iberoamérica, said in a statement. 

"Doctors will need to take a case-by-case approach when advising an overweight adult on losing weight," add Madrid, a professor at the Universidad de Valparaíso School of Medicine.

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Experts who were not part of the review told Fox News Digital the findings align with some recent data about intermittent fasting.

"There's been some suggestion in the data coming out over the last couple of years that, when it comes to weight, intermittent fasting may not be better than a standard low-calorie diet," said Dr. Gillian Goddard, a New York-based board-certified endocrinologist and adjunct assistant professor of medicine at New York University's Grossman School of Medicine.

"All diets are just tools," Goddard added. "You need to find the tool that best fits you for the long run — and if intermittent fasting is the tool that works best for you, then great. If not, there are lots of other tools at our disposal."

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Sustainability is the key to long-term weight loss, she noted.

Goddard said she has seen intermittent fasting work for Type 2 diabetes patients, because delaying meals and avoiding late-night eating can improve blood sugar control, and for those who snack mindlessly at night.

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Malia Frey, a certified health coach and personal trainer in Minneapolis, also noted that, while intermittent fasting is simple and inexpensive, it doesn't address nutritional quality or underlying issues related to weight gain such as physiological issues or stress. 

"If someone really wants to try intermittent fasting, I would suggest that they try it for a few weeks, but then gradually transition to a more sustainable plan that promotes healthy eating," Frey said. 

She recommends tracking macronutrients — monitoring protein, carbohydrates and fats — or following plans such as the Mediterranean diet, a vegetarian diet or the heart-healthy DASH diet.

Fox News Digital reached out to the study authors for comment.