This study aimed to summarize earlier randomized controlled trials on the effects of ketogenic diet (KD) on body composition and anthropometric measures. Four databases were searched from inception to May 2020 using relevant keywords. All clinical trials investigating the effects of KD on body weight (BW), body mass index (BMI), waist circumference (WC), fat mass (FM), fat-free mass (FFM), lean body mass (LBM), visceral adipose tissue (VAT) and percentage body fat (PBF) in adults were included. Overall, 18 trials were included in the review. Pooled effect sizes revealed a significant effect of KD on BW (weighted mean differences [WMD]: -2.87 kg, 95% confidence interval [CI]: -3.84 to -1.89), BMI (WMD: -1.44 kg/ 95% CI: -2.07, -0.81), FM (WMD: -1.40 kg, 95% CI: -2.50, -0.30), FFM (WMD: -0.81 kg, 95% CI: -1.32, -0.30), LBM (WMD: -0.63 kg, 95% CI: -1.21, -0.06), WC (WMD: -3.23 cm, 95% CI: -4.38, -2.09), VAT (WMD: -28.91 g, 95% CI: -50.57, -7.24) and PBF (WMD: -2.81 kg, 95% CI: -3.82, -1.80), respectively. Taken together, the data suggest that KD has beneficial effects on BW, BMI, FM, FFM, LBM, WC, VAT, and PBF. However, the effectiveness of the long term effect of this dietary pattern is unclear.
Keywords: Meta-analysis; ketogenic diet; obesity; weight.