Intermittent fasting shows similar benefits to traditional dieting for weight loss, study finds!
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Dr. Zhila Semnani-Azad and Professor John Sievenpiper from the Department of Nutritional Sciences, University of Toronto have published a new study showing that intermittent fasting is just as effective as traditional calorie-restriction diets for weight loss — with added benefits for heart health.
Published in the BMJ, their comprehensive review analyzed data from 99 randomized clinical trials involving over 6,500 participants. The findings revealed that individuals following intermittent fasting lost similar amounts of weight as those on calorie-restricted diets — averaging 1.7 to 2.5 kg more than people who ate without restrictions.
Importantly, intermittent fasting also led to improvements in cardiometabolic risk factors, including blood pressure, waist circumference, and cholesterol levels, when compared to unrestricted eating. Among the various intermittent fasting methods, alternate day fasting — fasting every other day — showed the greatest short-term benefits, leading to about 1.3 kg more weight loss than calorie restriction.
“When we started this project, intermittent fasting was all over the news,” says Semnani-Azad, who led the study while completing her PhD in Nutritional Sciences at U of T’s Temerty Faculty of Medicine. “We wanted to know if this strategy offered additional benefits over traditional approaches — and it turns out, it does offer a viable alternative.”
Their review is one of the most extensive to date, comparing three main forms of intermittent fasting:
Time-restricted eating (e.g., 16:8 method)
Whole-day fasting (e.g., 5:2 method)
Alternate day fasting
While all three methods showed similar long-term effects, alternate day fasting stood out in the short term for its impact on both weight loss and cardiometabolic health.
“These different weight loss strategies perform similarly overall,” says Semnani-Azad. “That means people can choose the approach that best fits their lifestyle and can be maintained over time.”
As GLP-1 weight-loss drugs like Ozempic rise in popularity, the researchers emphasize the importance of evidence-based, non-pharmaceutical options. “Nutrition isn’t one-size-fits-all,” adds Sievenpiper. “These findings support a personalized approach to weight management that empowers people to choose what works best for them.”
The study was funded by the Diabetes and Nutrition Study Group of the European Association for the Study of Diabetes and the Canadian Institutes of Health Research.
