Neoadjuvant Breast Cancer Time Restricted Eating

A phase II study to evaluate an innovative approach of following time restricted eating (TRE) in patients with HER2- negative breast cancer who will start neoadjuvant chemotherapy (NCT) for a new diagnosis of stage I-III breast cancer. Participants at baseline will have a body mass index (BMI) of (25-40) and engage in a TRE 16:8 schedule which includes 16 hours of fasting and 8 hours of eating. Patients will continue TRE for 16 weeks while receiving NCT. For patients who report at the time of the 2-3 week clinic visit that they are finding it challenging to adhere to the 16:8 TRE, instructions will be provided about alternative measures such as changing the time of the day they fast, dietary modifications and finally changing to a 14:10 schedule if other measures fail. For patients requiring NCT for longer than 16 weeks, they will be encouraged to continue TRE. Adherence calculation for the primary endpoint will include data for the first 16 weeks, and then monitored separately for any additional optional fasting beyond the first 16 weeks. Adherence to TRE will be self-reported by patients daily through electronic surveys through RedCap and approximately every 2-3 weeks (+/- 5 days) by the research team during their clinic visit.