Effects of therapeutic lifestyle change diets on blood lipids, lipoproteins, glycemic parameters, and blood pressure: a systematic review and meta-analysis of clinical trials

Abstract

CONTEXT: Cardiovascular disease is the leading cause of death worldwide. Low-calorie, low-fat therapeutic diets (TDs) developed by the US National Cholesterol Education Program, ie, the Step I and II diets and the therapeutic lifestyle changes diet, are approximately similar and are the initial therapeutic interventional approaches for lifestyle modification. OBJECTIVE: This systematic review with meta-analysis was undertaken to evaluate the effects of TDs diet on blood lipids, apolipoprotein A-1, apolipoprotein B, blood pressure, fasting blood glucose, and insulin. DATA SOURCES: A comprehensive search of the PubMed/MEDLINE, Web of Science, Scopus, and Google Scholar databases until October 2022 was performed to identify clinical trials investigating the effects of TDs on the aforementioned parameters. DATA EXTRACTION: One investigator screened the records and extracted data, and another reviewed the extracted data. DATA ANALYSIS: A total of 910 records were retrieved. After records were screened for eligibility, 34 clinical trials met the inclusion criteria. The pooled analysis from the random-effects model revealed a significant reduction in total cholesterol, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, apolipoprotein A-1, and apolipoprotein B in the TD intervention group vs the control group. The overall effects of TDs on fasting blood glucose, insulin, and blood pressure were not significant, but the results of subgroup analysis revealed a significant reduction in fasting blood glucose with the Step II diet and an intervention duration of more than 24 weeks. For blood pressure, the Step I diet and an intervention duration of more than 24 weeks resulted in significant reduction. There was no evidence of publication bias, but strong heterogeneity was observed. CONCLUSION: Therapeutic diets have promising effects on lipid profile parameters, glycemic indexes, and blood pressure, which can promote cardiovascular health. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration no. CRD42021259355.