Study of the Body’s Response to Exercise and a Plant-Based Diet in Overweight Postmenopausal Women with Hormone Receptor Positive Stage I-III Breast Cancer

Inclusion Criteria

• Patients with histologically-confirmed, hormone receptor (HR)-positive (estrogen receptor [ER] and/or progesterone receptor [PR]), stage 1-3 breast cancer
• Completed anti-HER2 therapy, if HER2-positive
• Postmenopausal status, defined as one of the following: * Lack of menses for 2 years * Oophorectomy * Medical ovarian suppression * Estradiol level of =< 30 pg/mL
• At least 3 months post completion of chemotherapy, if administered
• At least 3 months post radiation, if administered
• Receiving adjuvant endocrine therapy with an aromatase inhibitor (anastrozole, letrozole, exemestane)
• Sedentary (i.e., performing < 150 minutes/week of structured moderate-intensity or strenuous-intensity exercise)
• Age >= 18
• Body mass index (BMI) >= 27
• Able to achieve an acceptable peak baseline cardiopulmonary exercise testing (CPET), as defined by any of the following criteria and in the absence of high-risk ECG findings or other inappropriate response to exercise as determined by the investigator: * Achieved a plateau in oxygen consumption, concurrent with an increase in power output * A respiratory exchange ratio >= 1.10 * Attainment of maximal predicted heart rate (HRmax) (i.e., within 10 beats per minute [bpm] of age-predicted HRmax [HRmax = 220 – age (years)]) * Volitional exhaustion, as measured by a rating of perceived exertion (RPE) >= 18 on the BORG scale
• Willingness to comply with all study-related procedures
• Intact breast available for biopsy

Exclusion Criteria

• Presence of metastatic disease
• Any concurrent malignancy requiring active treatment with the exception of selective estrogen receptor modulators and aromatase inhibitors
• Insulin-dependent diabetes mellitus or non-insulin dependent diabetes mellitus on insulin therapy
• Enrollment onto any other interventional investigational study except interventions determined by the principal investigator (PI) not to confound the effect of exercise or diet on study outcomes
• Mental impairment leading to inability to cooperate
• Any of the following contraindications to exercise: * Acute myocardial infarction within 3–5 days of any planned study procedures * Unstable angina * Uncontrolled arrhythmia causing symptoms or hemodynamic compromise * Recurrent syncope * Active endocarditis * Acute myocarditis or pericarditis * Symptomatic severe aortic stenosis * Uncontrolled heart failure * Acute pulmonary embolus or pulmonary infarction within 3 months of any planned study procedures * Thrombosis of lower extremities * Suspected dissecting aneurysm * Uncontrolled asthma * Pulmonary edema * Respiratory failure * Acute non-cardiopulmonary disorders that may affect exercise performance
• Any other condition or intercurrent illness that, in the opinion of the investigator, makes the subject a poor candidate for study participation
• Nut or legume allergy
• Concurrent participation in weight loss programs