Pre-operative SABR With and Without Caloric Restriction for Early Stage Breast Cancer

Inclusion Criteria: * • Patients with pathologically proven DCIS or invasive breast cancer histologies * Willing and able to provide informed consent * Willing and able to comply with study treatments including dietary intervention * Body mass index (BMI) \>= 21 at time of enrollment * Age \>= 40 years at time of consent \* Patients with triple negative breast cancer (TNBC) must be \>= 50 years of age at time of consent * Karnofsky performance status (KPS) score 70 - 100 * Tumor size =\< 3.0 cm * Gross disease within the breast must be unifocal \* Gross disease may be multifocal as long as the total extent of tumor, gross and microscopic, occupies a volume with greatest dimension =\< 3 cm * Patients with invasive disease are required to have clinical axillary staging including axillary ultrasound (US) that proves patient is clinically node negative or can be done by physical examination if the patient is over 70 * Patient is not being considered for preoperative chemotherapy * Must be English or Spanish speaking Exclusion Criteria: * Patient is clinically node positive: clinically suspicious axillary lymph node(s) by axillary US or exam unless biopsied and found to be negative * Patient has stage IV metastatic disease \* Patients with oligo-metastatic disease who are being treated with curative intent per the treating physician will not be excluded if all other eligibility criteria are met * Breast tumor size is \> 3.0 cm * Positive non-axillary sentinel nodes or evidence of suspicious supraclavicular, infraclavicular, or internal mammary nodes by imaging or physical exam, unless biopsied and found to be negative for tumor * Evidence by physical examination or mammography of other suspicious masses, densities, or microcalcifications in either breast, unless biopsied and found to be benign * Paget's disease of the nipple * Previous breast radiation on ipsilateral side * Any prior treatment with radiation therapy or chemotherapy for the current breast cancer diagnosis prior to registration * Patients with significant psychiatric illness that would preclude them from adhering to the protocol in the judgement of the treating clinician * BMI \< 21 at the time of study enrollment