Feasibility and Acceptibility of a Multi-site Trial of Time Restircted Eating During Chemotheraply for Breast Cancer.

Little is known about how nutrition therapy can affect breast cancer treatment outcomes. Current standard care suggests enough daily calories and protein to maintain body weight and avoid muscle loss. However, this approach may be antiquated given weight gain is common during treatment and emerging pre-clinical and clinical evidence suggest that fasting during chemotherapy may improve clinical and patient-reported outcomes. For example, preliminary human trials examining the fasting mimicking diet (very low-calorie, low-protein diet 1-week per month) or short-term fasting (48-120 hours (h)), known as periodic fasting, surrounding chemotherapy may increase effectiveness of treatment and decrease side effects related to chemotherapy. Yet these diets have low adherence, side effects of their own, and may increase patient burden and decrease quality of life. In contrast, time restricted eating (TRE) is a form of intermittent fasting with high adherence that may have similar positive effects on treatment outcomes without the untoward side-effects. Moreover, TRE may have beneficial effects on glucose regulation and body composition (i.e., decreased weight and body fat gain) suggesting the potential importance of this regimen to breast cancer recurrence. TRE is extremely accessible with no calorie counting or financial burden to the patient, individuals just shorten their eating window daily. The aim of this trial is to examine the feasibility and acceptability of 24-weeks of 8-h TRE among female breast cancer patients initiating chemotherapy. Additionally the preliminary effect of 8-h TRE on treatment outcomes, treatment related side-effects, and patient reported quality of life and fatigue will be explored. Exploratory outcomes will include glucose regulation, body weight, body composition, IGF-1, IGFBP3, SHBG, estradiol (e2), TNF-alpha, and hsCRP