Inclusion Criteria:

          -  Histologically confirmed breast cancer

          -  4.1.2 Planning to start adjuvant hormonal therapy using an aromatase inhibitor or has
             started adjuvant hormonal therapy using an aromatase inhibitor within 14 days of
             randomization.

          -  Able to read, write, and understand English

          -  BMI ≥ 24 kg/m2

          -  Age ≥ 18 years

          -  If Her-2 positive, completed Herceptin therapy prior to enrollment

          -  ER and/or PR positive (defined as having ≥ 1% staining for ER and/or PR on IHC)

          -  Post-menopausal

               -  The absence of menstrual cycles in women who have not undergone hysterectomy for
                  at least 12 months preceding cancer diagnosis OR

               -  History of a bilateral oophorectomy OR

               -  History of a hysterectomy and age >55 OR

               -  No menses for <1 year with FSh and estradiol levels in postmenopausal range
                  according to institutional standards

          -  ECOG Performance Status 0 or 1

          -  Female

          -  Written informed consent obtained from subject and ability for subject to comply with
             requirements of the study

        Exclusion Criteria:

          -  Use of hormonal therapy other than aromatase inhibitors

          -  History of other malignancy within the past 5 years, except for malignancies with a >
             95% likelihood of cure (e.g. thyroid cancer, non-melanoma skin cancer)

          -  Already consuming a severe carbohydrate restricted (<20 g carbohydrates per day) diet
             or vegetarian diet

          -  Plans to start chemotherapy or HER2 targeted therapy

          -  Medical comorbidities that in the opinion of the investigator limits the patient's
             ability to complete the study

          -  Symptomatic metastases (Metastases allowed if asymptomatic)

          -  Current use of appetite suppressant medications

          -  Current use of any weight loss medications including herbal weight loss supplements or
             if patients are enrolled in a diet/weight loss program