This dieting approach may be more effective than intermittent fasting, scientists say

 Alternate-day fasting works better at boosting metabolism compared to both calorie restriction and intermittent fasting, a new study suggests.

Nearly 2.5 billion adults, or about 43 per cent of the global adult population, are overweight, with around 890 million living with obesity, according to the World Health Organization.

Doctors recommend weight loss for this segment of the population to reduce metabolic risk factors like high blood pressure, elevated cholesterol and increased blood sugar levels, all of which contribute to diabetes and heart disease.

Intermittent fasting, which involves cycling between periods of eating and fasting on a regular schedule, is sometimes recommended as an alternative to traditional calorie-restricted diets for weight loss.

This may include time-restricted eating, typically involving a 16-hour fasting period followed by an eight-hour eating window.

Another form of fasting is alternate-day fasting, which involves a 24-hour fast every other day.

But the health benefits of various forms of fasting compared to continuous caloric restriction and an unrestricted diet have remained largely unclear so far.

In a new study, researchers analysed the results of 99 randomised clinical trials involving 6,582 adult men and women to compare the effects of intermittent fasting diets with continuous calorie restriction or unrestricted diets on body weight and metabolic risk factors.

The study participants had an average body mass index of 31, and nearly 90 per cent had pre-existing health conditions.

Researchers found that alternate-day fasting was the only dietary strategy which provided a modest benefit in reducing body weight compared to continuous calorie restriction.

This form of fasting was also associated with lower levels of total and LDL, or "bad" cholesterol compared to time-restricted eating.

However, researchers noted that even alternate-day fasting did not meet the clinically significant threshold of at least 2kg of weight loss for individuals with obesity.

They cautioned that "longer-duration trials are needed to further substantiate these findings".

"Additional high quality randomised clinical trials, with extended durations beyond 52 weeks, are needed to elucidate the long-term effects of these dietary strategies," they said in the study, "with greater emphasis between intermittent fasting and its impact on cardiometabolic health across diverse populations."

For now, they said, alternate-day fasting could be added to the therapeutic toolkit for managing weight and metabolic health.

"Intermittent fasting does not aim to replace other dietary strategies, but to integrate and complement them within a comprehensive, patient-centered nutritional care model," they noted.

The Independent