Effects of intermittent fasting and energy-restricted diets on lipid profile: A systematic review and meta-analysis
Haiyan Meng Nutrition Available online 12 March 2020, 110801
Highlights
• Besides Ramadan IF, specific IF strategies may be adopted into clinical scenario.
• IF and ERD are effective in improving circulating TC, LDL-C and TG levels.
• However, IF and ERD have no meaningful effects on HDL-C levels.
BACKGROUND
To the best of our knowledge, no systematic review and meta-analysis has evaluated the cholesterol-lowering effects of intermittent fasting (IF) and energy-restricted diets (ERD) compared with control groups.
OBJECTIVE
The aim of the present systematic review and meta-analysis was to summarize the effects of controlled clinical trials examining the influence of IF and ERD on lipid profiles.
METHODS
A systematic review of four independent databases (PubMed/Medline, Scopus, Web of Science and Google Scholar) was performed to identify clinical trials reporting the effects of IF or ERD, relative to non-diet controls, on lipid profiles in humans. A random-effects model, employing the method of DerSimonian and Laird, was used to evaluate effect sizes, and results were expressed as weighted mean difference (WMD) and 95% confidence intervals (CI). Heterogeneity between studies was calculated using Higgins I2, with values ≥50% considered to represent high heterogeneity. Subgroup analyses were performed to examine the influence of intervention type, baseline lipid concentrations, degree of energy deficit, sex, health status and intervention duration.
RESULTS
For the outcomes of low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and triglycerides (TG), there were 34, 33, 35, and 33 studies meeting all inclusion criteria, respectively. Overall, results from the random-effects model indicated that IF and ERD interventions resulted significant changes in TC (WMD: -6.93 mg/dL, 95% CI: -10.18, -3.67, p <0.001; I2 = 78.2%), LDL-C (WMD: -6.16 mg/dL, 95% CI: -8.42, -3.90, p ˂0.001; I2 = 52 %), and TG concentrations (WMD: -6.46 mg/dL, 95% CI: -10.64, -2.27, p = 0.002; I2 = 61%). HDL-C concentrations did not change significantly following IF or ERD (WMD: 0.50 mg/dL, 95% CI: -0.69, 1.70, p = 0.411; I2 = 80%). Subgroup analyses indicated potentially differential effects between subgroups for one or more lipid parameter in the majority of analyses.
CONCLUSION
Relative to a non-diet control, IF and ERD are effective for the improvement of circulating TC, LDL-C and TG concentrations, but have no meaningful effects on HDL-C concentration. These effects are influenced by several factors which may inform clinical practice and future research. The present results suggest that these dietary practices are a means of enhancing the lipid profile in humans.
