Aim: To assess whether intermittent fasting (IF) diets are associated with improvement in weight loss, metabolic parameters, and subjective well-being, in people with obesity.
Data synthesis: We performed a Meta-analysis of Randomized Controlled Trials longer than 2 months, retrieved through an extensive search on MedLine, Cochrane CENTRAL Library, and Embase online databases, comparing weight loss with IF diets and control diets in people with Body Mass index (BMI) > 30 kg/m2. We retrieved 9 trials, enrolling 540 patients. IF was not associated with a significantly greater reduction of body weight or BMI at any time point with respect to controls or in respect to continuous restricted diets, with low-to moderate quality of evidence; no significant difference in efficacy between alternate day fasting and time restricted eating was found. Differences in fasting plasma glucose, total or high-density lipoprotein cholesterol or blood pressure at any time point were not statistically significant, whereas a reduction of low-density lipoprotein cholesterol (MD -8.39 [-15.96, -0.81] mg/dl, P = 0.03; I2 = 0%) was observed at 2-4 months, but not in the longer term. Data on psychological parameters and overall well-being were insufficient to perform a formal meta-analysis, whereas a qualitative synthesis did not show any difference between IF and controls.
Conclusions: IF is not associated with greater or lesser weight loss than non-intermittent fasting diets. Further data on psychological parameters and overall well-being are needed to properly assess the role of IF diets in the management of obesity.
Keywords: Intermittent fasting; Meta-analysis; Obesity; Weight loss.
Copyright © 2023 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.