The effect of fasting and energy restricting diets on markers of glucose and insulin controls: a systematic review and meta-analysis of randomized controlled trials
Somaye Fatahi, Ali Nazary-Vannani, Mohammad Hassan Sohouli, Zeinab Mokhtari, Hamed Kord‐Varkaneh, Vihan Moodi, Shing Cheng Tan, Teck Yew Low, Fernando Zanghelini, Farzad Shidfar
Abstract
Somaye Fatahiab, Ali Nazary-Vannanic, Mohammad Hassan Sohouliab, Zeinab Mokhtaride, Hamed Kord-Varkanehd, Vihan Moodifg, Shing Cheng Tanh, Teck Yew Lowh, Fernando Zanghelinii & Farzad Shidfarb*a Student Research Committee, Faculty of Public Health Branch, Iran University of Medical Sciences, Tehran, Iranb Department of Nutrition, School of Public Health, Iran University of Medical Sciences, Tehran, Iranc Students’ Scientific Research Center (SSRC), Department of Cellular and Molecular Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences (TUMS), Tehran, Irand Student Research Committee, Department of Clinical Nutrition and Dietetics, Faculty of Nutrition and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Irane Department of Clinical Nutrition and dietetics, Faculty of Nutrition 12 Sciences and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iranf School of Medicine, Tehran University of Medical Sciences, Tehran, Irang Students’ Scientific Research Center (SSRC), Tehran University of Medical Sciences (TUMS), Tehran, Iranh UKM Medical Molecular Biology Institute, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysiai National Institute for Health Research (NIHR) Innovation Observatory, Newcastle University, Newcastle Upon Tyne, UKSupplemental data for this article can be accessed at https://doi.org/10.1080/10408398.2020.1798350* Present address: Postgraduate Program in Therapeutic Innovation, University Federal of Pernambuco, Av. Prof. Moraes Rego, 1235 - Cidade Universitária, Recife, Pernambuco, Brazil.CONTACT Farzad Shidfar [email protected] Department of Nutrition, School of Public Health, Iran University of Medical Sciences, Teheran, Iran.AbstractInconsistencies exist with regard to influence of fasting and energy-restricting diets on markers of glucose and insulin controls. To address these controversial, this study was conducted to determine the impact of fasting diets on fasting blood sugars (FBSs), insulin, homeostatic model assessment insulin resistance (HOMA-IR) and hemoglobin A1c (HbA1c) levels. A comprehensive systematic search was carried out in electronic databases, i.e., Scopus, PubMed, and Web of Science through June 2019 for RCTs that investigated the impact of fasting and energy-restricting diets on circulating FBS, insulin, HOMA-IR and HbA1c levels from. Weighted mean difference (WMD) with the 95% CI were used for estimating combined effect size. The subgroup analysis was applied to specify the source of heterogeneity among articles. Pooled results from 30 eligible articles with 35 arms demonstrated a significant decrease in FBS (WMD): −3.376 mg/dl, 95% CI: −5.159, −1.594, p < 0.001), insulin (WMD: −1.288 μU/ml, 95% CI: −2.385, −0.191, p = 0.021), HOMA-IR (WMD: −0.41 mg/dl, 95% CI: −0.71, −0.10, p = 0.01) levels following fasting or energy-restricting diets. Nevertheless, no significant changes were observed in serum HbA1c levels. The subgroup analyses showed that overweight or obese people with energy restricting diets and treatment duration >8 weeks had a greater reduction in FBS, insulin and HOMA-IR level compared with other subgroups. The evidence from available studies suggests that the fasting or energy-restricting diets leads to significant reductions in FBS, insulin and HOMA-IR level and has modest, but, non-significant effects on HbA1c levels.