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

This phase II trial studies the effect of calorie reduction while undergoing stereotactic ablative radiation therapy in treating patients with breast cancer. Stereotactic ablative radiation therapy (sABR) is a highly focused radiation treatment that gives an intense dose of radiation concentrated on a tumor, while limiting the dose to the surrounding organ. Giving SABR before surgery may make the tumor smaller. Adding dietary restrictions in combination with radiation therapy may help increase local control and decrease the spread of the cancer to other places in the body. The purpose of this trial is to identify if there is a decrease in tumor tissue in patients undergoing caloric restriction during pre-operative SABR, compared to patients undergoing pre-operative SABR alone.