Intermittent Fasting Not Superior for Weight Loss, Review Finds

YEREVAN (Azat TV) – A comprehensive new Cochrane review has found that intermittent fasting, a popular dietary trend, is unlikely to lead to greater weight loss in overweight or obese adults compared to traditional dietary advice or making no changes at all. The findings, published in February 2026, challenge the widespread enthusiasm for this approach, often promoted on social media as a biological shortcut to weight management.

The review, spearheaded by Luis Garegnani, lead author from the Universidad Hospital Italiano de Buenos Aires Cochrane Associate Centre, analyzed evidence from 22 randomized clinical trials. These trials involved 1,995 adults across various continents, including North America, Europe, China, Australia, and South America, with most studies tracking participants for up to 12 months. The research examined multiple forms of intermittent fasting, such as alternate-day fasting, periodic fasting, and time-restricted feeding.

Cochrane Review Challenges Intermittent Fasting Hype

Despite the significant public health problem of obesity, which affected 2.5 billion adults globally in 2022 and is a leading cause of death and certain cancers, the review concluded that intermittent fasting does not offer a clinically meaningful advantage for weight loss. “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 stated, adding, “Intermittent fasting just doesn’t seem to work for overweight or obese adults trying to lose weight.”

The researchers also found little to no impact on participants’ quality of life or the incidence of adverse events. While there was no major effect on lipids like total cholesterol or triglycerides, the review noted a potential, albeit uncertain, increase in ‘good cholesterol.’ Furthermore, subgroup analyses suggested men might be more prone to adverse events than women when following intermittent fasting, though more research is needed in this area.

Expert Perspectives on Sustainability and Diet Quality

Nutritionists and medical professionals echoed the review’s cautious stance. Kim Pearson, a nutritionist specializing in weight loss, told The Independent that intermittent fasting is ‘not a magic solution.’ She highlighted that while it can help reduce calorie intake, improving overall diet quality is more crucial. Pearson emphasized that “more aggressive approaches are often difficult to sustain and do not address the root causes of weight gain, such as poor diet quality, excess ultra-processed foods and blood sugar instability.” She advocates for focusing on protein, fiber, and healthy fats while reducing ultra-processed foods, sugar, and refined starches to naturally regulate appetite and support stable blood sugar.

Rob Hobson, a registered nutritionist, warned that restrictive eating windows could lead to compensatory overeating and low energy, undermining long-term consistency essential for weight loss. Dr. Earim Chaudry, chief medical officer at online pharmacy Voy, added that limiting eating windows does not address the biological drivers of appetite and metabolic adaptation, making it difficult to sustain over time.

Intermittent Fasting as an Adjuvant, Not a Cure

Dr. Priya Kalia, a family medicine and obesity medicine board-certified doctor not involved in the Cochrane review, shared a nuanced perspective with Medical News Today. She emphasized that intermittent fasting should be viewed as a “dietary structure, adjuvant, not a metabolic therapy.” Dr. Kalia suggested that if a patient finds it simple, sustainable, and effective for reducing calories without adverse effects, it could be a reasonable option. However, she cautioned against marketing it as metabolically superior, stressing that “the strongest predictors of metabolic improvement remain the fundamentals: sustained weight loss, diet quality, physical activity, sleep, and — when appropriate — evidence-based medications like GLP-1 receptor agonists.”

Similarly, Dr. Mir Ali, a bariatric surgeon, noted that time-restricted eating can be effective, especially when combined with a balanced, nutrient-dense diet. He advises patients interested in this approach to start with a shorter 12-hour fasting window and gradually extend it, prioritizing proper nutrition with adequate protein, vegetables, and minimal refined carbohydrates and added sugars.

Preliminary Research Offers Contrasting Views

Despite the broad conclusions of the Cochrane review, some preliminary research suggests specific forms of time-restricted eating may offer benefits. Findings presented at the European Congress on Obesity in Malaga indicated that overweight and obese individuals who adopted an eight-hour time-restricted eating pattern successfully lost weight and maintained it over a year. Dr. Alba Camacho-Cardenosa from the University of Granada, lead author of this preliminary study, noted that restricting the eating window to eight hours for three months resulted in significant weight loss (3-4kg on average) that was largely maintained for at least a year, compared to control groups who lost less. Dr. Jonatan Ruiz, study co-ordinator, highlighted its potential as a simpler, less tedious method than daily calorie counting, but underscored the need for larger, longer-term studies.

While the robust Cochrane review casts doubt on the broad claims of intermittent fasting for superior weight loss, the emerging, albeit preliminary, evidence for specific time-restricted eating patterns, particularly when combined with dietary quality improvements, suggests that this field of research is still evolving. Patients considering intermittent fasting should consult their doctors, focusing on sustainable, holistic approaches to health rather than viewing any single method as a standalone ‘magic solution.’