This study aims to compare the effects of genotype-based dietary counseling with standard dietary counseling based on general recommendations on weight loss and reduction of body fat. Participants will receive individualized dietary guidance either informed by genetic information or based on conventional dietary guidelines. Changes in body weight and body composition will be assessed over the course of the intervention.

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

Individual participant data will not be shared outside the research team.