The purpose of this randomized clinical trial is to examine the effects of Mediterranean diet based intervention on inflammation and metabolic risk factors in overweight or obese postmenopausal women with breast cancer receiving adjuvant hormone therapy.

Inclusion Criteria:

• Breast cancer patients who are receiving adjuvant hormone therapy after diagnosed with breast cancer stage Ⅰ-Ⅲ and have completed cancer treatment including breast surgery and/or adjuvant chemotherapy, radiotherapy
• Postmenopausal women
• Body mass index (BMI) ≥23 kg/m2
• Able to speak and read Korean
• Able to comply with all required study procedures and schedule
• Willing and able to give written informed consent

Exclusion Criteria:

• Participants with cancer recurrence or metastasis
• Participants with weight change more than 5kg in the previous 3 months
• Participants with secondary causes of obesity, such as hypothyroidism
• Participants with hepatic disease (aspartate aminotransferase (AST)/alanine aminotransferase (ALT) >3 x institutional upper limit of normal) or renal disease (serum creatinine >2.0 mg/dL)
• Participants with serious psychiatric illness, including bipolar disorder, schizophrenia, or other psychosis, bulimia, anorexia nervosa, or suicidal ideation
• Participants who are taking weight loss medications
• Participants who are receiving systemic corticosteroid therapy
• Participants with alcohol abuse or dependence
• Any condition which in the opinion of the investigator makes the subject unsuitable for inclusion in this study