The dieting technique has been hailed as a game-changer, but new research says not to believe the hype
The evidence behind intermittent fasting “doesn’t justify the enthusiasm” about the dieting technique, experts have said. A number of celebrities and politicians have reportedly used intermittent fasting to stay trim, but a new study suggests that science does not back it.
There are a number of different intermittent fasting techniques. Alternate day fasting involves a 24-hour fast on every second day, and has become more popular in recent years. Another approach is time-restricted eating, where people only eat for a certain number of hours in the day, such at the 16:8 diet involving a 16-hour fasting period followed by an eight-hour eating.
Whole-day fasting includes the 5:2 diet involving five days of eating and two days of fasting periods. Now a new Cochrane review has examined 22 trials examining intermittent fasting involving 1,995 adults across North America, Europe, China, Australia, and South America.
The studies examined multiple forms of intermittent fasting, including alternate-day fasting, periodic fasting, and time-restricted eating. The international team of researchers, led by academics in Argentina, compared intermittent fasting with traditional dietary advice.
But the authors concluded that “intermittent fasting may result in little to no difference in weight loss, measured as change from starting weight”. “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.
“Intermittent fasting may be a reasonable option for some people, but the current evidence doesn’t justify the enthusiasm we see on social media. Obesity is a chronic condition. Short-term trials make it difficult to guide long-term decision-making for patients and clinicians.”
Eva Madrid, senior author of the paper from Cochrane Evidence Synthesis Unit Iberoamerica, added: “With the current evidence available, it’s hard to make a general recommendation. Doctors will need to take a case-by-case approach when advising an overweight adult on losing weight.”
The Health Survey for England, publishing January, found that 30% of adults are obese while 66% are either overweight or living with obesity. The figures, released by NHS Digital, show that more than a quarter (27%) of adults in England are inactive – meaning they do less than 30 minutes of moderate or vigorous activity a week.
Meanwhile, 48% of adults had raised cholesterol.
