Neoadjuvant Breast Cancer Time Restricted Eating

Inclusion Criterion

Individuals must meet all of the following inclusion criteria in order to be eligible to participate in the study:

1. Patient must be ≥ 18 years of age at time of consent and must be able to understand and provide informed consent.

2. BMI 25-40 at time of enrollment.

3. Patients must have an ECOG performance status of 0 or 1.

4. Patient must have a recent diagnosis of histologically confirmed primary invasive breast carcinoma.

5. Multifocal or contralateral DCIS or invasive breast cancers are allowed if the breast cancers meet the same eligibility criteria for ER/PR and HER2.

6. Oligometastatic disease is allowed if treating physician recommends standard neoadjuvant chemotherapy.

7. Tumor status must be HER2 negative per ASCO/CAP guidelines (determined by local testing).

8. Patients must have clinical stage I-III (utilizing TNM criterion) at diagnosis.

9. Clinical T size must be ≥ 1.5cm if there is no radiographic or clinical evidence of axillary lymph node involvement. Any size tumor is allowed if axillary lymph nodes appear to be involved.

10. Patient must be willing and able (have no contraindication) to receive recommended standard neoadjuvant therapy consisting of at least 16 weeks of planned neoadjuvant chemotherapy.

a. Acceptable regimen includes doxorubicin and cytoxan followed by a taxane The schedule will be determined by treating physician. Carboplatin and pembrolizumab can also be added to the neoadjuvant chemotherapy regimen if determined to be appropriate by treating physician.

9. Patients must have organ and marrow function adequate for initiating neoadjuvant chemotherapy as determined by their treating physician.

10. Patient must be willing and able (have no contraindication) to participate in TRE consisting of 16 weeks

11. Women of childbearing potential and sexually active males must use accepted and effective method(s) of contraception or abstain from sexual intercourse for the duration of their participation in the study and for 6 months after the last study intervention.

12. Patient must have a personal email address, an internet-capable device, and the ability/ willingness to read and reply to email every day for the duration of the study.

Exclusion Criteria

An individual who meets any of the following criteria will be excluded from participation in this study:

1. Clinical T4 and/or N3 disease, including inflammatory breast cancer.

2. Any prior treatment for the current breast cancer diagnosis, including surgery, chemotherapy, radiation, or experimental therapy.

3. Women must not be pregnant or breast-feeding due to the potential harm to an unborn fetus and possible risk for adverse events in nursing infants with the treatment regimens being used. Patients must also not expect to conceive from the time of registration, while on study treatment, and until at least 6 months after the last study intervention.

4. Patients with type 1 diabetes, or type 2 diabetes treated with insulin.

5. Patients with a history of eating disorder or taking weight loss medications

6. Patients who actively smoke

7. Patients who work night shifts or on a rotating shift schedule.

8. Patients must not have impaired decision-making capacity.

9. Patients who are not English speaking as study staff is only able to provide the study intervention measurement tool.

10. Patients that are >2 weeks into starting neoadjuvant chemotherapy regimen.