Effects of Mediterranean Diet Based Intervention in Breast Cancer Patients

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