London [UK], June 19 (ANI): Intermittent fasting may be just as effective as traditional calorie-restricted diets for helping people lose weight, according to a comprehensive new review published in The BMJ.

The study suggests that certain fasting methods, such as alternate-day fasting, might offer slightly greater benefits. However, researchers caution that longer-term studies are needed to confirm these effects.

The findings come amid rising global concern about obesity. As of 2022, the World Health Organisation estimated that around 2.5 billion adults worldwide were overweight, and nearly 900 million were classified as obese.

Obesity significantly increases the risk of chronic illnesses like type 2 diabetes, cardiovascular disease, and high blood pressure.

Intermittent fasting, an eating pattern that involves cycles of fasting and eating, has grown in popularity as an alternative to traditional calorie-counting diets. However, questions have remained about whether it is equally effective or more beneficial in the long run.

To address this, researchers reviewed data from 99 randomised clinical trials involving more than 6,500 adults, most of whom had pre-existing health conditions and an average BMI of 31.

The studies lasted anywhere from three to 52 weeks, and covered a variety of intermittent fasting styles, including:

Time-restricted eating (e.g., 16:8 method)Alternate day fasting (24-hour fast every other day)Whole day fasting (e.g., the 5:2 diet)

All forms of intermittent fasting and continuous calorie restriction resulted in small weight reductions compared to diets with no calorie control.

Among the fasting types, alternate-day fasting showed the most notable, though still modest, advantage, producing slightly more weight loss than calorie restriction and other intermittent fasting strategies.

Compared to continuous calorie restriction, alternate-day fasting led to an average additional weight loss of 1.29 kg.

It also outperformed time-restricted eating and whole-day fasting by 1.69 kg and 1.05 kg, respectively. However, these differences did not meet the minimum threshold of 2 kg, which the study defined as clinically significant for individuals with obesity.

In terms of cardiometabolic health, alternate-day fasting appeared to reduce total and LDL ('bad') cholesterol more effectively than time-restricted eating.

Conversely, time-restricted eating was associated with a slight increase in cholesterol compared to whole-day fasting. No notable improvements were observed in blood sugar levels or HDL ('good') cholesterol for any fasting method.

Notably, weight loss was mainly seen in studies lasting less than 24 weeks. Among longer trials (24 weeks or more), benefits were only evident when comparing structured diets to unrestricted eating patterns.

The authors acknowledged several limitations, including high variability between the types of fasting, small sample sizes in many studies, and overall low to moderate confidence in the evidence.

Nevertheless, this review is among the first to offer a broad comparative view across all major diet strategies using rigorous methods.

'The current evidence provides some indication that intermittent fasting diets have similar benefits to continuous energy restriction for weight loss and cardiometabolic risk factors,' the study authors concluded, emphasising the need for longer-term research.

A linked editorial from experts in Colombia noted that the strength of any dietary plan may lie as much in structure and professional support as in the specific method used.

They highlighted that alternate-day fasting should not be viewed as a replacement but as a complementary option in personalised nutritional care.

'Focusing on sustainable changes over time is essential,' the editorial stated, adding, 'Intermittent fasting can play a role within a holistic, patient-centred approach to nutrition.' (ANI)