This single-arm study is designed to test the hypothesis that a six-month intermittent fasting (IF) intervention is feasible for patients to adhere to and improves health-related quality of life while subjects are on adjuvant endocrine therapy (AET).
Breast cancer patients ≥ 18 years old who are willing to consent to an approximately 14-hour nighttime fasting period and an approximately 10-hour daytime eating period.
Histologically and/or cytologically confirmed diagnosis of estrogen receptor (ER) positive (ER+) and human epidermal growth factor receptor (HER) 2 negative (HER2-) localized breast cancer (stages I-III).
Progesterone receptor positive or negative patients are allowed.
Hormone receptor positivity is defined as ER positivity in at least 1% cells by immunohistochemistry (IHC). HER 2-negative breast cancer is defined as a negative in situ hybridization test or an IHC status of 0, 1+ or 2+. If IHC is 2+, a negative in situ hybridization fluorescence in situ hybridisation (FISH), chromogenic in situ hybridization (CISH), or silver-enhanced in situ hybridization (SISH) test is required.
Subject who works late night shifts.
Subject that was or currently on a fasting diet (e.g., Keto diets), intervention, or an agent (e.g., Ozempic) for the explicit purpose of inducing weight loss in the past one year.
Subject with a history of an eating disorder (e.g., anorexia nervosa, bulimia nervosa).
Presence of diabetes.