THE IMPACT OF INTERMITTENT FASTING ON WEIGHT REDUCTION AND METABOLIC PARAMETERS — CURRENT STATE OF KNOWLEDGE

Abstract

Background: Intermittent fasting (IF) has emerged as a widely investigated dietary strategy for the management of obesity and metabolic disorders. Increasing evidence suggests that periodic energy restriction may improve body weight and metabolic parameters associated with cardiovascular disease and type 2 diabetes. Aim: This review aimed to summarize the current evidence regarding the effects of intermittent fasting on body weight reduction, glucose–insulin metabolism, lipid profile, blood pressure, and inflammatory markers. Methods: A narrative review of the literature indexed in PubMed was conducted, focusing primarily on publications from 2020–2025, including randomized controlled trials, systematic reviews, umbrella reviews, and meta-analyses evaluating intermittent fasting in adults with overweight, obesity, metabolic syndrome, or type 2 diabetes. Results: Current evidence indicates that IF may promote moderate weight reduction, decrease visceral adiposity, improve insulin sensitivity, reduce fasting glucose and triglyceride concentrations, and modestly lower blood pressure. Early time-restricted eating appears particularly beneficial due to its alignment with circadian rhythms. However, most studies demonstrate that IF does not significantly outperform conventional caloric restriction when total energy deficit is comparable. Conclusions: Intermittent fasting represents a promising nutritional strategy for improving metabolic health, particularly in individuals with obesity and metabolic syndrome. Nevertheless, long-term adherence, dietary quality, and sustained energy deficit remain the primary determinants of clinical effectiveness. Further long-term randomized controlled trials are required to establish the optimal IF protocols and their long-term safety.