Comparison of Genotype-Based Dietary Counseling Versus Standard Dietary Counseling on Weight Loss and Fat Mass Reduction

Inclusion Criteria: * Adults aged ≥18 years * Body mass index (BMI) ≥25 kg/m² * Greek-speaking (able to read and understand Greek and provide informed consent) * Willing and able to participate in dietary counseling and study assessments for the duration of the study Exclusion Criteria: * Current use of pharmacological treatments for weight loss, including but not limited to GLP-1 receptor agonists, appetite suppressants, or other anti-obesity medications * Participation in any structured weight-loss intervention or program within the previous 3 months, including commercial weight-loss programs or medically supervised dietary interventions * Use of medications known to significantly affect body weight or body composition, such as systemic corticosteroids, antipsychotic medications, or medications for thyroid disorders * Pregnancy or lactation * Presence of medical conditions that may affect body weight, metabolism, or nutritional status, including untreated thyroid disease, severe gastrointestinal disorders, or endocrine disorders