Intermittent fasting versus continuous caloric restriction for glycemic control and weight loss in type 2 diabetes: A traditional review

Prim Care Diabetes. 2025 Jun;19(3):203-213. doi: 10.1016/j.pcd.2025.02.006. Epub 2025 Feb 24.

Abstract

Type 2 Diabetes Mellitus (T2DM) represents a major global health issue, with its incidence anticipated to increase markedly in the forthcoming decades. Efficient non-pharmacological therapies, especially dietary approaches, are essential for regulating glycemic control and facilitating weight reduction. Intermittent Fasting (IF) and Continuous Caloric Restriction (CCR) are two well researched methodologies, but their relative effectiveness and enduring advantages continue to be topics of active discussion. This review systematically assesses and contrasts the impacts of intermittent fasting (IF) and continuous calorie restriction (CCR) on glycemic regulation and weight reduction in persons with type 2 diabetes mellitus (T2DM), highlighting their short-term and long-term effects, safety profiles, and adherence rates. A thorough literature analysis was performed utilizing PubMed and Google Scholar, concentrating on papers published from 2000 to 2024. The review encompassed randomized controlled trials and observational studies that investigated the effects of intermittent fasting (IF) and continuous calorie restriction (CCR) on glycemic indicators (HbA1c, fasting glucose) and body weight. IF shown substantial short-term advantages, encompassing marked decreases in HbA1c levels, fasting glucose, and body weight. Mechanistic discoveries emphasized better insulin sensitivity, augmented fat metabolism, and autophagy as key aspects. In contrast, CCR was linked to enduring metabolic enhancements, including decreased visceral fat and improved insulin sensitivity. Nevertheless, both dietary approaches demonstrated constraints.

Keywords: Autophagy; Continuous caloric restriction; Dietary interventions; Glycemic control; Insulin sensitivity; Intermittent fasting; Metabolic health; Non-pharmacological management; Type 2 diabetes mellitus; Weight loss.

Publication types

  • Systematic Review

MeSH terms

  • Biomarkers / blood
  • Blood Glucose* / metabolism
  • Caloric Restriction* / adverse effects
  • Caloric Restriction* / methods
  • Diabetes Mellitus, Type 2* / blood
  • Diabetes Mellitus, Type 2* / diagnosis
  • Diabetes Mellitus, Type 2* / diet therapy
  • Diabetes Mellitus, Type 2* / physiopathology
  • Fasting* / blood
  • Glycated Hemoglobin / metabolism
  • Glycemic Control* / adverse effects
  • Humans
  • Intermittent Fasting
  • Time Factors
  • Treatment Outcome
  • Weight Loss*

Substances

  • Blood Glucose
  • Biomarkers
  • hemoglobin A1c protein, human
  • Glycated Hemoglobin