{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,24]],"date-time":"2026-07-24T11:03:14Z","timestamp":1784890994996,"version":"3.55.0"},"reference-count":49,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2026,7,24]],"date-time":"2026-07-24T00:00:00Z","timestamp":1784851200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>Background\/Objectives: Male obesity secondary hypogonadism (MOSH) is a highly prevalent condition characterised by reduced testosterone levels in obese men, driven by increased aromatase activity, reduced SHBG, insulin resistance, and HPG axis suppression. Dietary interventions represent a cornerstone of non-pharmacological management; however, the comparative efficacy of different dietary patterns on testosterone restoration remains unclear. Methods: We conducted a systematic literature review following PRISMA 2020 guidelines. Comprehensive searches were performed in SciSpace, Google Scholar, and PubMed through June 2026. Eligible studies included human adult males with obesity (BMI \u2265 30 kg\/m2) undergoing Mediterranean diet (MedDiet), ketogenic diet (KD\/VLCKD), or intermittent fasting (IF) interventions, with quantitative assessment of testosterone or androgen status. Results: From 697 initial records, 500 unique papers were identified after deduplication. Following abstract screening (n = 442 excluded) and full-text assessment (n = 6 excluded), 52 studies were included in the final synthesis. VLCKD demonstrated the most consistent evidence for testosterone improvement, with RCTs reporting significant increases in total testosterone (+1.5 to +3.0 nmol\/L). Intermittent fasting showed promising but more heterogeneous results. Evidence for Mediterranean diet was limited, focusing primarily on metabolic rather than hormonal outcomes. Weight loss emerged as a critical mediator across all dietary interventions (~3 nmol\/L per 10 kg weight loss). Conclusions: Among dietary interventions for MOSH, VLCKD shows the strongest evidence for testosterone restoration in obese men, through rapid weight loss, improved insulin sensitivity, reduced inflammation, and potential direct HPG axis effects. Intermittent fasting represents a viable alternative. Mediterranean diet, while beneficial for cardiovascular health, lacks robust interventional evidence for testosterone improvement in this population. Systematic Review Registration: This review was not prospectively registered. PROSPERO registration is recommended for future updates.<\/jats:p>","DOI":"10.3390\/nu18152417","type":"journal-article","created":{"date-parts":[[2026,7,24]],"date-time":"2026-07-24T10:38:41Z","timestamp":1784889521000},"page":"2417","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Dietary Interventions and Testosterone Levels in Obese Men: A Systematic Review Comparing the Mediterranean Diet, Ketogenic Diet, and Intermittent Fasting"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7113-2372","authenticated-orcid":false,"given":"Sandro","family":"La Vignera","sequence":"first","affiliation":[{"name":"Department of Clinical and Experimental Medicine, University of Catania, Via S. Sofia 78, 95123 Catania, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5217-9343","authenticated-orcid":false,"given":"Rosita A.","family":"Condorelli","sequence":"additional","affiliation":[{"name":"Department of Clinical and Experimental Medicine, University of Catania, Via S. Sofia 78, 95123 Catania, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1067","DOI":"10.1210\/jc.2016-3580","article-title":"A perspective on middle-aged and older men with functional hypogonadism: Focus on holistic management","volume":"102","author":"Grossmann","year":"2017","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"2643","DOI":"10.1210\/jc.2010-2724","article-title":"Update: Hypogonadotropic hypogonadism in type 2 diabetes and obesity","volume":"96","author":"Dandona","year":"2011","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"549","DOI":"10.1210\/jc.2006-1859","article-title":"The relative contributions of aging, health, and lifestyle factors to serum testosterone decline in men","volume":"92","author":"Travison","year":"2007","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1810","DOI":"10.1210\/jc.2009-1796","article-title":"Characteristics of secondary, primary, and compensated hypogonadism in aging men: Evidence from the European Male Ageing Study","volume":"95","author":"Tajar","year":"2010","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"578","DOI":"10.1016\/j.amjmed.2010.12.027","article-title":"Testosterone deficiency","volume":"124","author":"Traish","year":"2011","journal-title":"Am. J. Med."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"673","DOI":"10.1038\/nrendo.2009.212","article-title":"Testosterone deficiency, insulin resistance and the metabolic syndrome","volume":"5","author":"Zitzmann","year":"2009","journal-title":"Nat. Rev. Endocrinol."},{"key":"ref_7","first-page":"1140","article-title":"Attenuated luteinizing hormone (LH) pulse amplitude but normal LH pulse frequency, and its relation to plasma androgens in hypogonadism of obese men","volume":"76","author":"Vermeulen","year":"1993","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"619","DOI":"10.2164\/jandrol.106.000125","article-title":"Obesity and male reproductive potential","volume":"27","author":"Hammoud","year":"2006","journal-title":"J. Androl."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"460","DOI":"10.1210\/jcem-67-3-460","article-title":"Inhibition of sex hormone-binding globulin production in the human hepatoma (Hep G2) cell line by insulin and prolactin","volume":"67","author":"Plymate","year":"1988","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"407","DOI":"10.1038\/s41574-020-0363-7","article-title":"Metabolic regulation of kisspeptin\u2014The link between energy balance and reproduction","volume":"16","author":"Navarro","year":"2020","journal-title":"Nat. Rev. Endocrinol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"107","DOI":"10.1080\/13685530802317934","article-title":"Hypogonadotrophic hypogonadism in type 2 diabetic patients","volume":"11","author":"Dandona","year":"2008","journal-title":"Aging Male"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1186\/s12610-016-0034-7","article-title":"Gut endotoxin leading to a decline IN gonadal function (GELDING)\u2014A novel theory for the development of late onset hypogonadism in obese men","volume":"26","author":"Tremellen","year":"2016","journal-title":"Basic Clin. Androl."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1715","DOI":"10.1210\/jc.2018-00229","article-title":"Testosterone therapy in men with hypogonadism: An Endocrine Society clinical practice guideline","volume":"103","author":"Bhasin","year":"2018","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"2341","DOI":"10.1210\/jc.2011-0118","article-title":"Low testosterone in men with type 2 diabetes: Significance and treatment","volume":"96","author":"Grossmann","year":"2011","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1148","DOI":"10.1111\/j.1471-0528.2006.00990.x","article-title":"The impact of obesity on reproduction in women with a focus on polycystic ovary syndrome","volume":"113","author":"Pasquali","year":"2006","journal-title":"BJOG"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"445","DOI":"10.1530\/EJE-12-0890","article-title":"Age-associated changes in hypothalamic-pituitary-testicular function in middle-aged and older men are modified by weight change and lifestyle factors: Longitudinal results from the European Male Ageing Study","volume":"168","author":"Camacho","year":"2013","journal-title":"Eur. J. Endocrinol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"e34","DOI":"10.1056\/NEJMoa1800389","article-title":"Primary prevention of cardiovascular disease with a Mediterranean diet supplemented with extra-virgin olive oil or nuts","volume":"378","author":"Estruch","year":"2018","journal-title":"N. Engl. J. Med."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"779","DOI":"10.1161\/CIRCRESAHA.118.313348","article-title":"The Mediterranean diet and cardiovascular health","volume":"124","author":"Gea","year":"2019","journal-title":"Circ. Res."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"789","DOI":"10.1038\/ejcn.2013.116","article-title":"Beyond weight loss: A review of the therapeutic uses of very-low-carbohydrate (ketogenic) diets","volume":"67","author":"Paoli","year":"2013","journal-title":"Eur. J. Clin. Nutr."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1365","DOI":"10.1007\/s40618-019-01061-2","article-title":"Very-low-calorie ketogenic diet (VLCKD) in the management of metabolic diseases: Systematic review and consensus statement from the Italian Society of Endocrinology (SIE)","volume":"42","author":"Caprio","year":"2019","journal-title":"J. Endocrinol. Investig."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1048","DOI":"10.1016\/j.cmet.2016.06.001","article-title":"Fasting, circadian rhythms, and time-restricted feeding in healthy lifespan","volume":"23","author":"Longo","year":"2016","journal-title":"Cell Metab."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"46","DOI":"10.1016\/j.arr.2016.10.005","article-title":"Impact of intermittent fasting on health and disease processes","volume":"39","author":"Mattson","year":"2017","journal-title":"Ageing Res. Rev."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"n71","DOI":"10.1136\/bmj.n71","article-title":"The PRISMA 2020 statement: An updated guideline for reporting systematic reviews","volume":"372","author":"Page","year":"2021","journal-title":"BMJ"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Bruci, A., Tuccinardi, D., Tozzi, R., Balena, A., Santucci, S., Frontani, R., Mariani, S., Basciani, S., Spera, G., and Gnessi, L. (2020). Very low-calorie ketogenic diet: A safe and effective tool for weight loss in patients with obesity and mild kidney failure. Nutrients, 12.","DOI":"10.3390\/nu12020333"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"2086","DOI":"10.1111\/dom.13773","article-title":"Mechanisms underlying the cardiometabolic protective effect of walnut consumption in obese people: A cross-over, randomized, double-blind, controlled inpatient physiology study","volume":"21","author":"Tuccinardi","year":"2019","journal-title":"Diabetes Obes. Metab."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"e3203","DOI":"10.1002\/dmrr.3203","article-title":"Childhood obesity: Aetiology, comorbidities, and treatment","volume":"35","year":"2019","journal-title":"Diabetes Metab. Res. Rev."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Moriconi, E., Camajani, E., Fabbri, A., Lenzi, A., and Caprio, M. (2021). Very-low-calorie ketogenic diet as a safe and valuable tool for long-term glycemic management in patients with obesity and type 2 diabetes. Nutrients, 13.","DOI":"10.3390\/nu13030758"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Colleluori, G., Chen, R., Turin, C.G., Vigevano, F., Qualls, C., Johnson, B., Mediwala, S., Villareal, D.T., and Armamento-Villareal, R. (2020). Aromatase inhibitors plus weight loss improves the hormonal profile of obese hypogonadal men without causing major side effects. Front. Endocrinol., 11.","DOI":"10.3389\/fendo.2020.00277"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"R99","DOI":"10.1530\/EJE-15-0262","article-title":"Therapy of endocrine disease: Testosterone supplementation and body composition: Results from a meta-analysis study","volume":"174","author":"Corona","year":"2016","journal-title":"Eur. J. Endocrinol."},{"key":"ref_30","first-page":"997","article-title":"Pathogenesis of the decreased androgen levels in obese men","volume":"79","author":"Giagulli","year":"1994","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_31","first-page":"654","article-title":"Insulin regulates testosterone and sex hormone-binding globulin concentrations in adult normal weight and obese men","volume":"80","author":"Pasquali","year":"1995","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"344","DOI":"10.1111\/cen.12664","article-title":"Effects of testosterone treatment on glucose metabolism and symptoms in men with type 2 diabetes and the metabolic syndrome: A systematic review and meta-analysis of randomized controlled clinical trials","volume":"83","author":"Grossmann","year":"2015","journal-title":"Clin. Endocrinol."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Rondanelli, M., Gasparri, C., Pirola, M., Barrile, G.C., Moroni, A., Sajoux, I., and Perna, S. (2024). Does the Ketogenic Diet Mediate Inflammation Markers in Obese and Overweight Adults? A Systematic Review and Meta-Analysis of Randomized Clinical Trials. Nutrients, 16.","DOI":"10.3390\/nu16234002"},{"key":"ref_34","first-page":"105274","article-title":"Protective Effect of TNFAIP3 on Testosterone Production in Leydig Cells under an Aging Inflammatory Microenvironment","volume":"115","author":"Xing","year":"2023","journal-title":"Arch. Gerontol. Geriatr."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"930","DOI":"10.1001\/jamainternmed.2017.0936","article-title":"Effect of alternate-day fasting on weight loss, weight maintenance, and cardioprotection among metabolically healthy obese adults: A randomized clinical trial","volume":"177","author":"Trepanowski","year":"2017","journal-title":"JAMA Intern. Med."},{"key":"ref_36","first-page":"1","article-title":"Metabolic syndrome with involvement of the male reproductive system","volume":"1","author":"Saldivar","year":"2022","journal-title":"J. Reprod."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1186\/1742-4755-8-24","article-title":"Does weight loss improve semen quality and reproductive hormones?","volume":"8","author":"Thulstrup","year":"2011","journal-title":"Reprod. Health"},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"La Vignera, S., and Condorelli, R.A. (2026). Effects of intermittent fasting on male and female reproductive hormones, fertility, and sexual function: A comprehensive review with emphasis on the existing evidence gap in women. Nutrients, 18.","DOI":"10.3390\/nu18111817"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"36","DOI":"10.1016\/j.clnesp.2024.11.001","article-title":"Effects of time-restricted feeding and weight-loaded swimming test on androgen levels and androgen receptor expression in orchiectomized male Wistar rats","volume":"65","author":"Liow","year":"2025","journal-title":"Clin. Nutr. ESPEN"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"85","DOI":"10.1007\/s44337-025-00289-7","article-title":"Intermittent fasting is beneficial for body weight regulation and reproductive phenotypes in high-fat diet-fed male mice","volume":"2","author":"Buranaamnuay","year":"2025","journal-title":"Discov. Med."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Di Vincenzo, A., Busetto, L., Vettor, R., and Rossato, M. (2018). Obesity, male reproductive function and bariatric surgery. Front. Endocrinol., 9.","DOI":"10.3389\/fendo.2018.00769"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"e948180","DOI":"10.12659\/MSM.948180","article-title":"Mechanisms of Leydig cell aging and obesity-related hypogonadism in men: A review","volume":"31","author":"Huang","year":"2025","journal-title":"Med. Sci. Monit."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"RD24187","DOI":"10.1071\/RD24187","article-title":"Intermittent fasting restores fertility dysfunction caused by a high-fat diet in male rats: Role of SIRT-1\/NRF2\/P38 MAPK\/NLRPReprod","volume":"37","author":"Hemead","year":"2025","journal-title":"Fertil. Dev."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"274","DOI":"10.23736\/S2724-6507.23.04024-1","article-title":"Positive effects of dietary supplementation with nutraceuticals on male subclinical hypogonadism: A pilot study","volume":"48","author":"Iuliano","year":"2023","journal-title":"Minerva Endocrinol."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"662","DOI":"10.1038\/oby.2001.90","article-title":"The effects of metformin and diet on plasma testosterone and leptin levels in obese men","volume":"9","author":"Ozata","year":"2001","journal-title":"Obes. Res."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"e814","DOI":"10.1210\/clinem\/dgae249","article-title":"Metabolic Effects of Testosterone Added to Intensive Lifestyle Intervention in Older Men with Obesity and Hypogonadism","volume":"110","author":"Barnouin","year":"2025","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"827","DOI":"10.1210\/jcem-60-5-827","article-title":"Effect of carbohydrate supplementation on reproductive hormones during fasting in men","volume":"60","author":"Kyung","year":"1985","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"302","DOI":"10.1210\/js.2017-00062","article-title":"Effect of testosterone treatment on adipokines and gut hormones in obese men on a hypocaloric diet","volume":"1","author":"Tang","year":"2017","journal-title":"J. Endocr. Soc."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"1834","DOI":"10.1210\/jc.2007-2177","article-title":"Low testosterone levels are common and associated with insulin resistance in men with diabetes","volume":"93","author":"Grossmann","year":"2008","journal-title":"J. Clin. Endocrinol. Metab."}],"container-title":["Nutrients"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-6643\/18\/15\/2417\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,24]],"date-time":"2026-07-24T10:48:13Z","timestamp":1784890093000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-6643\/18\/15\/2417"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7,24]]},"references-count":49,"journal-issue":{"issue":"15","published-online":{"date-parts":[[2026,8]]}},"alternative-id":["nu18152417"],"URL":"https:\/\/doi.org\/10.3390\/nu18152417","relation":{},"ISSN":["2072-6643"],"issn-type":[{"value":"2072-6643","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,7,24]]}}}