{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T05:46:44Z","timestamp":1780638404541,"version":"3.54.1"},"reference-count":33,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2025,9,11]],"date-time":"2025-09-11T00:00:00Z","timestamp":1757548800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Italian Ministry of Health\u2014Current research IRCCS"},{"name":"ISOMED srl"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>Background: Elevated BMI in women is linked to metabolic and endocrine imbalances that impair fertility and increase pregnancy risks. While &gt;10% weight loss before an Assisted reproductive technology (ART) treatment may improve outcomes, sustained results through conventional diets are challenging. A very-low calorie ketogenic diet (VLCKD) promotes rapid fat loss while preserving lean mass and may offer long-term benefits. This study evaluated the efficacy (\u226510% weight loss without lean mass reduction), adherence, metabolic effects, and pregnancy outcomes of a meal replacement VLCKD in women with overweight or obesity scheduled for ART. Methods: This monocentric, prospective case-series was conducted at the Obesity and Work Center, Fondazione IRCCS Ca\u2019 Granda Ospedale Maggiore Policlinico, Milan (September 2019\u2013September 2023). Eligible women underwent a three-phase dietary program: a 3-month VLCKD (&lt;800 kcal\/day), a 6-month transition with gradual carbohydrate reintroduction, and a Mediterranean-style maintenance diet. Participants were monitored for safety, body composition, adherence, and biochemical changes. Results: Of 52 women enrolled, 40 initiated the VLCKD; 27 (68%) achieved \u226510% weight loss while preserving lean mass. Eleven conceived naturally during or after the diet; 22 underwent ART, with 12 additional pregnancies. This corresponds to a 58% pregnancy rate among those who began the VLCKD. Significant improvements were observed in body mass index (BMI), fat mass, waist circumference, glucose metabolism, lipid profile, and liver function. No adverse events were reported. Conclusions: A meal replacement VLCKD protocol is feasible, well-tolerated, and associated with significant improvements in weight, especially in body composition, metabolic health, and potentially outcomes in women with overweight or obesity awaiting ART.<\/jats:p>","DOI":"10.3390\/nu17182930","type":"journal-article","created":{"date-parts":[[2025,9,11]],"date-time":"2025-09-11T14:23:50Z","timestamp":1757600630000},"page":"2930","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Prospective Observational Case Series in Infertile Women with Overweight or Obesity Treated with a Very-Low Calorie Ketogenic Diet (VLCKD) Prior to an In Vitro Fertilization (IVF) Treatment"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0015-3157","authenticated-orcid":false,"given":"Ma\u00edra","family":"Casalechi","sequence":"first","affiliation":[{"name":"Infertility Unit, Fondazione IRCCS Ca\u2019 Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alessandra","family":"Piontini","sequence":"additional","affiliation":[{"name":"Occupational Health Unit, Obesity and Work Center, Fondazione IRCCS Ca\u2019 Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Annaelisa","family":"Nicolosi","sequence":"additional","affiliation":[{"name":"Infertility Unit, Fondazione IRCCS Ca\u2019 Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Francesca","family":"Bergomas","sequence":"additional","affiliation":[{"name":"Occupational Health Unit, Obesity and Work Center, Fondazione IRCCS Ca\u2019 Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Filomena","family":"Napolitano","sequence":"additional","affiliation":[{"name":"Laboratory of Clinical Chemistry and Microbiology, Fondazione IRCCS Ca\u2019 Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9178-0713","authenticated-orcid":false,"given":"Stefano","family":"Turolo","sequence":"additional","affiliation":[{"name":"Nephrology Dialysis and Pediatric Transplantation Unit, Fondazione IRCCS Ca\u2019 Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marco","family":"Reschini","sequence":"additional","affiliation":[{"name":"Infertility Unit, Fondazione IRCCS Ca\u2019 Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alessandra","family":"Riccaboni","sequence":"additional","affiliation":[{"name":"Infertility Unit, Fondazione IRCCS Ca\u2019 Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Roberta","family":"Bellinghieri","sequence":"additional","affiliation":[{"name":"Infertility Unit, Fondazione IRCCS Ca\u2019 Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Edgardo","family":"Somigliana","sequence":"additional","affiliation":[{"name":"Infertility Unit, Fondazione IRCCS Ca\u2019 Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy"},{"name":"Department of Clinical Sciences and Community Health, Universit\u00e0 Degli Studi di Milano, 20122 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5014-721X","authenticated-orcid":false,"given":"Luisella","family":"Vigna","sequence":"additional","affiliation":[{"name":"Occupational Health Unit, Obesity and Work Center, Fondazione IRCCS Ca\u2019 Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,9,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Zheng, L., Yang, L., Guo, Z., Yao, N., Zhang, S., and Pu, P. 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