Is intermittent fasting worth the hype?

By Stephen Beech

Trendy intermittent fasting fails to match the hype when it comes to losing weight, according to new research.

It is no better than traditional diets when it comes to shedding the pounds, say scientists.

Intermittent fasting plans such as "16:8" - where eating is limited to an eight-hour window every day - are adopted by celebrities including Jennifer Aniston, Halle Berry and Wolverine actor Hugh Jackman for fitness and weight management.

But a new study shows that intermittent fasting is unlikely to lead to greater weight loss for overweight or obese adults than traditional dietary advice or doing nothing at all.

Obesity has more than tripled globally since 1975, according to the World Health Organisation (WHO) with an estimated 2.5 billion adults overweight.

Intermittent fasting has surged in popularity in recent years, fueled by social media, lifestyle influencers, and claims of rapid weight loss and other health benefits.

To check on its effectiveness, researchers analysed evidence from 22 clinical trials involving 1,995 adults across Europe, North America, Australia, China and South America.

Trials examined multiple forms of intermittent fasting, including alternate-day fasting, periodic fasting, and time-restricted feeding.

Most studies followed participants for up to 12 months.

The review compared intermittent fasting with traditional dietary advice and with no intervention at all.

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Intermittent fasting did not appear to have a clinically meaningful effect on weight loss compared to standard dietary advice or doing nothing, according to the findings published in the journal Cochrane Database of Systematic Reviews.

Reporting of side effects was "inconsistent" across the trials, which the research team said made it difficult to draw firm conclusions.

Review lead author Professor Luis Garegnani said: “Intermittent fasting just doesn’t seem to work for overweight or obese adults trying to lose weight."

Garegani also cautioned against the hype surrounding fasting online.

He said: “Intermittent fasting may be a reasonable option for some people, but the current evidence doesn’t justify the enthusiasm we see on social media."

Garegnani, from the Universidad Hospital Italiano de Buenos Aires Cochrane Associate Centre, Argentina, says few trials have looked at the long-term results of intermittent fasting.

He added: “Obesity is a chronic condition.

"Short-term trials make it difficult to guide long-term decision-making for patients and clinicians."

The majority of the included studies enrolled predominantly white people in high-income countries.

As obesity is a rapidly growing issue in low- and middle-income countries, the researchers say further studies are needed.

Study senior author Professor Eva Madrid, from Cochrane Evidence Synthesis Unit Iberoamerica, said: “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.”