Longer-term effects of intermittent fasting on body composition and cardiometabolic health in adults with overweight and obesity: A systematic review and meta-analysis

Abstract

The aim of the present study was to investigate the effects of long-term intermittent fasting (IF) on body composition and cardiometabolic health in adults with overweight and obesity. PubMed, Web of Science, and Scopus were searched from inception to March 2024 to identify original randomized trials that investigated the effects of IF versus either a control diet (CON) and/or continuous caloric restriction (CR). Participants were adults with overweight and obesity and intervention durations were ≥ 6 months. Overall, a total of 24 studies involving 2032 participants were included in the meta-analysis. Compared with CON, IF significantly reduced body weight [WMD: -2.84 kg], BMI [WMD: -1.41 kg.m²], fat mass [WMD: -3.06 kg], fat-free mass [WMD: -0.81 kg], waist circumference [WMD: -3.85 cm], visceral fat [SMD: -0.37], fasting glucose [WMD: -0.14 mmol/l], triglycerides [WMD: -0.12 mmol/l], and diastolic blood pressure [WMD: -2.24 mmHg]. Conversely, IF significantly increased high-density lipoproteins [WMD: 0.04 mmol/l] when compared with CON, but had no effects on insulin, hemoglobin A1c%, total cholesterol, low-density lipoprotein, or systolic blood pressure. Compared with CR, IF significantly reduced fat mass [WMD: -0.70 kg], body fat percentage [WMD: -0.59%], and DBP [WMD: -0.91 mmHg], and increased HDL [WMD: 0.03 mmol/l], with no other significant effects. Subgroup analyses showed that the mode of IF and intervention duration were the primary moderators of IF effects on the markers. In adults with overweight or obesity, IF and CR are comparably effective for reducing body weight and adiposity, as well as for improving cardiometabolic health markers.

Keywords: blood pressure; body composition; insulin resistance; intermittent fasting; lipid profile; obesity.