Effects of Ramadan intermittent fasting on hormones regulating appetite in healthy individuals: A systematic review and meta-analysis

Alogaiel, Deema M.; Alsuwaylihi, Abdulaziz; Alotaibi, May S.; Macdonald, Ian A.; Lobo, Dileep N.

Abstract

Background and aims
This systematic review and meta-analysis aimed to examine the effect of Ramadan intermittent fasting on appetite-regulating hormones including leptin, ghrelin, insulin, gastrin, glucagon-like peptide-1, peptide YY, and cholecystokinin.

Methods
We searched the MEDLINE, Embase, Cochrane Library, CINAHL, Google Scholar, and Web of Science databases to identify relevant research on appetite-regulating hormones during Ramadan intermittent fasting, published until the end of March 2024.

Results
Data from 16 eligible studies comprising 664 participants (341, 51.4% male) with a mean ± standard deviation age of 33.9 ± 10.8 years were included. The meta-analysis included 12 studies with complete leptin data, showing no significant effect of Ramadan intermittent fasting on leptin concentrations (standardised mean difference – SMD = -0.11 μg/mL, 95% CI: -0.36 to 0.14). Analysis of three studies with complete ghrelin data demonstrated a significant increase in ghrelin concentrations following Ramadan intermittent fasting (SMD = 0.31 pg/mL, 95% CI: 0.03 to 0.60). Six studies examining insulin concentrations pre- and post-fasting revealed no significant effect on insulin concentrations (SMD = -0. 24 μU/mL, 95% CI: -0.54 to 0.02). Similarly, analysis of three studies with complete gastrin data showed no significant effect of intermittent fasting on gastrin concentrations (SMD = 0.23 pg/mL, 95% CI: -0.71 to 0.99).

Conclusion
Ramadan intermittent fasting significantly increases ghrelin concentrations while showing no significant effects on leptin, insulin, and gastrin. While ghrelin findings were consistent across studies, the high heterogeneity in leptin studies suggests further research to better understand the effects of Ramadan intermittent fasting on appetite-regulating hormones.

Citation

Alogaiel, D. M., Alsuwaylihi, A., Alotaibi, M. S., Macdonald, I. A., & Lobo, D. N. (2025). Effects of Ramadan intermittent fasting on hormones regulating appetite in healthy individuals: A systematic review and meta-analysis. Clinical Nutrition, 45, 250-261. https://doi.org/10.1016/j.clnu.2025.01.005

• Journal Article Type: Review
• Acceptance Date: Jan 5, 2025
• Online Publication Date: Jan 6, 2025
• Publication Date: 2025-02
• Deposit Date: Jan 6, 2025
• Publicly Available Date: Jan 7, 2026
• Journal: Clinical Nutrition
• Print ISSN: 0261-5614
• Electronic ISSN: 1532-1983
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 45
• Pages: 250-261
• DOI: https://doi.org/10.1016/j.clnu.2025.01.005
• Keywords: Ramadan; Intermittent fasting; Appetite-regulating hormones; Meta-analysis; Systematic review
• Public URL: https://nottingham-repository.worktribe.com/output/43948241
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0261561425000068
• Additional Information: This article is maintained by: Elsevier; Article Title: Effects of Ramadan intermittent fasting on hormones regulating appetite in healthy individuals: A systematic review and meta-analysis; Journal Title: Clinical Nutrition; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.clnu.2025.01.005; Content Type: article; Copyright: © 2025 The Author(s). Published by Elsevier Ltd.