Effect of a Food for Special Medical Purposes on Muscle Mass Preservation During GLP-1 RAs Weight Loss Treatment

Inclusion Criteria: * Age ≥18 years and ≤ 65 years old; * BMI ≥ 30 Kg/m2 and ≤45 kg/m2 * BMI from 27 kg/m2 to 30 Kg/m2 with at least one associated co-morbidity related to overweight \[e.g. dysglycemia (pre-diabetes and/or metabolic syndrome), hypertension, dyslipidemia, obstructive sleep apnea syndrome (OSAS\], or cardiovascular disease\] * Starting to use a GLP-1 RAs (liraglutide, semaglutide) or dual GIP and GLP-1 RAs (tirzepatide) for weight reduction; patient can be enrolled if they start the treatment at the time of enrollment or up to 2 weeks * Diet composition adjusted to provide 0.9-1.1 g/Kg ideal body weight proteins * Signed informed consent Exclusion Criteria: * Type I and Type II diabetes; patients with pre-diabetes and/or metabolic syndrome and assuming Metformin and SGLT-2 inhibitors can be enrolled * Monogenic obesity (Subjects with a known diagnosis of monogenic obesity, including but not limited to pathogenic mutations in LEP, LEPR, MC4R, POMC, PCSK1, or other genes known to cause monogenic forms of early-onset or syndromic obesity) * Reduced kidney function, defined as eGFR \< 60 mL/min/1.73 m², calculated using the CKD-EPI equation (see Appendix 1) * Oncologic patients in active treatments * Hypersensitivity to any of the constituents of the study product * Pregnancy * Breastfeeding * Use of meal replacements for a diet enriched with aminoacids and/or HMB * Use of food supplements containing aminoacids and/or HMB; patients can be included in the study if they undergo a washout period of at least 15 days