• Pathologically proven invasive breast cancer

• Planned neoadjuvant chemotherapy determined by the judgment of the medical oncologist

• The patient must be female

• Age ≥ 18

• Non-metastatic and non-inflammatory breast cancer

• History/physical examination, including breast exam and documentation of weight and Karnofsky Performance Status of 80-100% for at least 60 days prior to study entry.

• Women of childbearing potential must be non-pregnant and non-lactating and willing to use medically acceptable form of contraception during chemotherapy

• Patient must capable of and provide study specific informed consent prior to study entry

• BMI ≥21

• Weight ≥120lbs

• No prior history of non-breast malignancies in the past 1 year unless it was a non- melanomatous skin lesion or carcinoma in situ of the cervix.

• Patient must not have Acquired Immune Deficiency Syndrome (AIDS) or HIV positive based upon current CDC definition; note, however, that HIV testing is not required for entry into this protocol. The need to exclude patients with AIDS or HIV from this protocol is necessary because anti-retrovirals may alter patient metabolism.

• Patient may not have any active Gastrointestinal/Malabsorption disorder at the discretion of the Principal Investigator which may include:

• Chronic Pancreatitis

• Chronic Diarrhea or Vomiting

• Active Eating Disorder

• No history of or current active drug/alcohol dependence.

• No patients with decisional impairment.