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Intermittent fasting comparable to conventional diets for weight loss

Intermittent fasting is equivalent but not superior to continuous calorie restriction for reducing weight, according to a study published in the American Journal of Clinical Nutrition.

“Although preliminary evidence suggests that intermittent calorie restriction exerts stronger effects on metabolic parameters, which may link obesity and major chronic diseases, compared with continuous calorie restriction, there is a lack of well-powered intervention studies,” Ruth Schübel, MD, from the German Cancer Research Center, Heidelberg, Germany, and colleagues wrote.

Schübel and colleagues conducted a randomized clinical trial to investigate whether intermittent fasting has better weight loss effects than conventional dieting. The researchers enrolled 150 overweight and obese nonsmokers aged between 35 and 65 years.

Participants were randomly assigned to one of three groups: intermittent calorie restriction, continuous calorie restriction or control. Those in the intermittent calorie restriction group went 5 days without calorie restriction and 2 days with 75% energy deficit for a net weekly energy deficit of about 20%. Those in the continuous calorie restriction group followed a diet with a daily energy deficit of about 20%. Those in the control group received no advice to restrict energy.

The intervention phase lasted 12 weeks, which was followed by a 12-week maintenance phase and a 26-week follow-up phase.

Over the intervention phase, participants in the intermittent calorie restriction group had a relative weight change of –7.1%, while those in the continuous calorie restriction group had a change of –5.2% and those in the control group had a change of –3.3%.

Weight loss was slightly greater in the intermittent calorie restriction group compared with the continuous calorie restriction group; however, the expression of 82 preselected genes in adipose tissue linking obesity to chronic diseases were not significantly different between the two groups.

At the final follow-up, participants in the intermittent calorie restriction group lost the most weight (–5.2%), followed by those in the continuous calorie restriction group (–4.9%) and the control group (–1.7%). There were similar changes in visceral and subcutaneous adipose tissue volumes. Several circulating metabolic biomarkers did not significantly differ between the intermittent calorie restriction group and the continuous calorie restriction group.

“This study indicated that intermittent calorie restriction and continuous calorie restriction are alternative energy restriction regimens for weight loss with comparable improvements to obesity-associated metabolic profiles, at least over 50 weeks,” Schübel and colleagues concluded. “Both regimens were well tolerated by the majority of participants and may be equivalent weight management approaches. Further investigations are needed on the effectiveness, practicability, and safety of ICR for patients with chronic diseases, such as type 2 diabetes, cardiovascular diseases, or cancer.” – by Alaina Tedesco

Disclosures: The authors report no relevant financial disclosures.