Dietary Strategies for the Treatment of Fibromyalgia in Overweight and Obese Patients

Spontaneous, non-sponsored, interventional, controlled, randomized, parallel-arm clinical study. Primary objective To assess the impact of specific dietary approaches (ketogenic diet, Mediterranean diet, or Mediterranean diet supplemented with GABA-producing probiotics, e.g., Bifidobacterium adolescentis PRL2019) on fibromyalgia (FM) severity-particularly pain, sleep quality, anxiety, and depression-using validated questionnaires in female patients with FM and overweight/class I obesity. Secondary objectives * Evaluate effects on anthropometric measures, metabolic profile, and body composition. * Assess changes in gut microbiota composition and metabolomic analysis. * Measure neurosteroids with positive allosteric activity on GABA-A or NMDA receptors in saliva and/or plasma. * Exploratory pilot sub-study to quantify brain GABA and glutamate levels through magnetic resonance spectroscopy (MRS) in a subset of patients. Methods Participants will be recruited from the Rheumatology Unit outpatient clinics of IRCCS Policlinico San Martino Hospital (Genoa). Eligible subjects will be adult women with FM and overweight/obesity, selected through protocol-defined criteria. Enrollment requires written informed consent. At enrollment (baseline), participants will complete validated questionnaires assessing FM severity (pain, sleep quality, depression, anxiety, bowel function). Data collection will include sociodemographic information, Mediterranean diet adherence through PREDIMED questionnaire, basal metabolic rate, medical and dietary history, smoking status, blood pressure, and recent laboratory results. Stool, blood, and saliva samples will be collected for routine tests, metabolomics, and ELISA-based measurement of neuroactive steroids like cortisol, progesterone, DHEA. Within 7 days T1, results will be reviewed and eligible participants randomized to one of three groups: hypocaloric ketogenic diet, Mediterranean diet, or Mediterranean diet plus probiotics. Individuali