Metabolic Impact of Intermittent Fasting in Patients With Type 2 Diabetes Mellitus: A Systematic Review and Meta-analysis of Interventional Studies

Abstract

Abstract Context Intermittent fasting (IF) has been proposed as a weight-loss strategy with additional cardiometabolic benefits in individuals with obesity. Despite its growing popularity, the effect of IF in patients with type 2 diabetes (T2DM) remains unclear. Objective We conducted a systematic review and meta-analysis to evaluate the metabolic impact of IF compared to standard diet in patients with T2DM. Methods Embase, PubMed, and clinicaltrials.gov between 1950 and August 12, 2020 were searched for randomized, diet-controlled studies evaluating any IF intervention in adults with T2DM. We examined the impact of IF on weight loss and glucose-lowering by calculating pooled estimates of the absolute differences in body weight and glycated hemoglobin A1c (HbA1c) compared to a control group using a random-effects model. Results Seven studies (n = 338 participants; mean body mass index [BMI] 35.65, mean baseline HbA1c 8.8%) met our inclusion criteria. IF induced a greater decrease in body weight by –1.89 kg (95% CI, –2.91 to –0.86 kg) compared to a regular diet, with no significant between-study heterogeneity (I2 21.0%, P = .28). The additional weight loss induced by IF was greater in studies with a heavier population (BMI > 36) (–3.43 kg [95% CI, –5.72 to –1.15 kg]) and in studies of shorter duration (≤ 4 months) (–3.73 kg [95% CI, –7.11 to –0.36 kg]). IF was not associated with further reduction in HbA1c compared to a standard diet (HbA1c –0.11% [95% CI, –0.38% to 0.17%]). Conclusion Current evidence suggests that IF is associated with greater weight loss in patients with T2DM compared with a standard diet, with a similar impact on glycemic control.