Intermittent Fasting Shows Similar Weight Loss to Standard Diets in Major Review

Recent scientific reviews have examined the effectiveness of intermittent fasting compared to traditional weight loss methods, focusing on adults with overweight or obesity across multiple studies.

The Cochrane Collaboration published a systematic review in February 2026 that evaluated 22 randomized controlled trials involving nearly 2,000 participants from different regions. The review included various intermittent fasting approaches such as alternate-day fasting, periodic fasting, and time-restricted feeding.

Findings from the Cochrane review indicate that intermittent fasting likely results in little to no difference in weight loss when compared to standard dietary advice. The analysis also found that intermittent fasting may offer little to no additional benefit in weight reduction compared to no intervention.

When comparing intermittent fasting to regular dietary advice, the review reported a mean difference in percentage weight loss from baseline of -0.33%, with low-certainty evidence. Against no intervention or waiting list, the mean difference was -3.42%, based on moderate-certainty evidence.

What the numbers show

• 22 randomized controlled trials included nearly 2,000 adults
• Mean difference in weight loss vs. standard advice: -0.33% (low-certainty
• Mean difference vs. no intervention: -3.42% (moderate-certainty
• 2024 meta-analysis: -2.05 kg weight, -0.73 kg/m² BMI reduction in adults over 40
• 2025 diabetes trial: 6.51% weight loss with fasting plus calorie restriction

A 2024 meta-analysis covering nine randomized controlled trials in adults over 40 with obesity but without metabolic disease found that intermittent fasting led to modest reductions in body weight, body mass index, fat mass, and triglycerides. No significant loss of lean body mass was observed in these studies.

Research published in 2025 involving people with type 2 diabetes assessed the effects of combining 12-hour night intermittent fasting with calorie restriction. This approach resulted in greater weight loss and improved HbA1c levels compared to calorie restriction alone.

Another 2025 study examined time-restricted eating without reducing calorie intake. The results showed no improvement in insulin sensitivity or cardiovascular markers, suggesting that calorie reduction, rather than meal timing, is responsible for metabolic benefits.

The Cochrane review and additional studies indicate that intermittent fasting does not provide clinically meaningful extra weight loss compared to standard diets based on daily calorie deficits. Across the trials, intermittent fasting produced only about a 3.4% greater weight loss than control groups.

* This article is based on publicly available information at the time of writing.