ORIGINAL RESEARCH article
Front. Nutr.
Sec. Clinical Nutrition
This article is part of the Research TopicAdvances in Bioelectrical Impedance Analysis for Clinical NutritionView all articles
The effects of a Very Low-Energy Ketogenic Therapy (VLEKT) on body composition, gut microbiota and metabolites in overweight subjects
Provisionally accepted
Yeganeh Manon Khazrai
Claudia Di Rosa*
Annamaria AltomareMarta GiovanettiLudovica Di Francesco
Greta Lattanzi
Chiara Spiezia
Antonella SimoneFederica Coccaro
Giulia CostaMichele Pier Luca GuarinoSilvia Manfrini- Campus Bio-Medico University, Rome, Italy
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Obesity is associated with chronic diseases and gut-brain axis disruptions, with diet influencing gut microbiota. This single-arm, uncontrolled study evaluated the effects of a 28 – day Very Low-Energy Ketogenic Therapy (VLEKT) on body weight, gut microbiota, and stool-derived metabolites in individuals with excess weight. Methods: Forty-one subjects with excess weight, from Campus Bio-Medico Foundation in Rome underwent nutritional consultations at baseline (T0), assessment including body measurements,anthropometry, bioimpedance analysis, and gut microbiota assessment profiling and . Participants completed FAST questionnaire to evaluate dietary intake and gastrointestinal symptoms before and after 28 days of VLEKT with meal replacements (T1). Follow-up was conducted at T1. Results: Thirty-one participants completed the studyintervention (T1). Results showed At T1, there were significant reductions in body weight, BMI, and fat mass. , and increases in fat-free mass and body water (p<0.05). Microbiota analysis revealed showed decreasedd Firmicutes and Actinobacteria, and increased Bacteroidetes and Verrucomicrobia. Notable ge Genus-level changes included increases in Bacteroides, Parabacteroides, and Akkermansia, and decreases in Streptococcus, Dorea, Blautia, Bifidobacterium, and Ruminococcus. Stool metabolites showed decreased Bbutyrate and lactate and levels decreased,increased while propionate, vitamin K2, and GABA increased (p<0.05). Because the study lacked a control group and did not include systemic biomarkers or biochemical confirmation of ketosis, microbiota and metabolite changes cannot be linked to physiological effects. Overall, findings indicate short-term weight loss and stool microbiota modulation, but all microbiota-related outcomes remain exploratory due to the small sample size, short duration, and uncontrolled design.Conclusion:
Keywords: gut metabolites, Ketogenic Diet, microbiota, Obesity, VLEKT
Received: 27 Sep 2025; Accepted: 08 Dec 2025.
Copyright: © 2025 Khazrai, Di Rosa, Altomare, Giovanetti, Di Francesco, Lattanzi, Spiezia, Simone, Coccaro, Costa, Guarino and Manfrini. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Claudia Di Rosa
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