February 20, 2026
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Intermittent fasting is unlikely to cause greater weight loss than traditional dieting methods or typical consumption habits, new research shows.
Intermittent fasting might not have the weight-loss benefits touted by many on social media, a new study finds.
The trendy diet focuses on when people are eating, not what they consume or how much. Some intermittent fasters only eat during an eight-hour span each day and fast for the other 16 hours. Others eat normally for five days of the week and then fast for two.
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The idea is that the body exhausts the calories consumed through food and then relies on fat stores, reducing weight through a process called metabolic switching. But a new research review from Argentina found that intermittent fasting is unlikely to lead to greater weight loss than following traditional dieting advise or not dieting.
"Intermittent fasting just doesn't seem to work for overweight or obese adults trying to lose weight," Luis Garegnani, lead author of the review, said in a news release.
The study examined data from 22 clinical trials worldwide involving nearly 2,000 adults. Those trials studied various types of intermittent fasting. In some trials, adults fasted for certain times of the day. In others, they fasted for days at a time.
Intermittent fasting has not been well studied, with little research on its long-term effects. Studies tend to have small sample sizes and inconsistent reporting, making it hard to draw conclusions, the scientists behind the research review said. Their review also was limited by a focus on white adults in affluent countries.
"With the current evidence available, it's hard to make a general recommendation," said Eva Madrid, a senior author of the research review. "Doctors will need to take a case-by-case approach when advising an overweight adult on losing weight."
Previous studies have found potential benefits for intermittent fasting beyond weight loss, including improvements in cognitive function and helping manage type 2 diabetes. However, it has also been linked to heart issues and disordered eating.
The findings of the research review support a 2023 report from the American Heart Association, which found that eating fewer large meals was more effective than adjusting the time of day that food is consumed. However, a 2025 study found that people who fasted for three nonconsecutive days each week lost slightly more weight compared to those who ate less all seven days of the week.
