Effectiveness and safety of intermittent fasting on blood pressure in adults with overweight or obesity: a systematic review

Previous intermittent fasting (IF) studies have reported inconsistent findings regarding its antihypertensive effects and safety. This study aimed to assess the effects and safety of IF on blood pressure (BP), anthropometrics, and cardiometabolic risk markers in individuals with overweight or obesity compared to a no-intervention control group. Relevant studies were retrieved from multiple databases, including CNKI, Wanfang, VIP, SinoMed, PubMed, Embase, the Cochrane Library, and Web of Science, up to April 30, 2024. A meta-analysis was performed using Stata version 18.0 and RevMan 5.4, calculating mean differences (MD) or risk ratios (RR) with 95% confidence intervals (CI) via the Knapp-Hartung modified random-effects model. Publication bias was evaluated using a contour-enhanced funnel plot and Egger’s test. Fifteen studies (n = 929) were included. IF significantly reduced systolic blood pressure (SBP) (MD = –4.43 mmHg, 95% CI: –5.83 to –3.03, p < 0.001) and diastolic blood pressure (DBP) (MD = –2.00 mmHg, 95% CI: –3.23 to –0.78, p < 0.001) compared to control. IF also improved anthropometric measures, Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), and Triglycerides (TG). Seven studies reported minor adverse effects. Although the IF group showed a higher risk of vomiting (RR = 1.11, 95% CI: 1.04–1.19, p = 0.01) and irritability (RR = 1.22, 95% CI: 1.13–1.31, p < 0.001) compared to the control group, these reactions were predominantly observed during the initial phase of the intervention and were self-resolving. IF significantly lowered SBP and DBP in individuals with overweight or obesity, particularly in high-risk subgroups (obesity, age ≥45 years, and prehypertension/hypertension), with a favorable safety profile. Due to heterogeneity, future trials should standardize IF regimens and target these subgroups to confirm generalizability. The review protocol has been registered on PROSPERO (CRD42024540777).