Dietary Restrictions, Physical Health, and Cardiovascular Risk: Mechanisms, Clinical Evidence, and Safety Considerations

Abstract

Background. Intermittent fasting (IF) has emerged as a prominent non-pharmacological strategy in lifestyle medicine and sports science, particularly in the context of cardiovascular disease (CVD) prevention and cardiometabolic optimization. Growing interest in IF reflects its potential to target cardiometabolic risk factors through time-dependent metabolic adaptations rather than continuous caloric restriction. Methods. This narrative review synthesizes current evidence derived from basic experimental research, clinical trials, and systematic reviews evaluating the cardiovascular, metabolic, and physical performance effects of intermittent fasting. The analysis focuses on three primary fasting regimens: time-restricted eating (TRE), alternate-day fasting (ADF), and modified fasting regimens (MFR). Results. Evidence demonstrates that IF induces metabolic switching from glucose utilization to fatty acid oxidation and ketone body production. These adaptations correlate with improvements in blood pressure, atherogenic lipid profiles, glucose–insulin homeostasis, and oxidative stress pathways. Mechanistic studies suggest enhanced autophagy, improved mitochondrial biogenesis, and circadian rhythm alignment contribute to cardiometabolic cardioprotection. However, data regarding long-term safety, hard cardiovascular endpoints, and potential risks such as transient energy deficits remain critical areas of ongoing evaluation. Conclusions. Intermittent fasting represents a highly effective lifestyle intervention for enhancing cardiometabolic health and reducing cardiovascular risk. While short- and medium-term outcomes are favorable, structured clinical oversight is necessary to ensure safety and long-term compliance in clinical and active populations.