Time Restricted Diet in Obese or Overweight Pre or Postmenopausal Participants

Inclusion Criteria:

Subjects must have a stable weight (have not gained or lost 25 pounds in the last 6 months)
Subjects must have had a normal mammogram within 9 months prior to registration; NOTE: subjects must also have a normal breast exam on the day of the pre-intervention random fine needle aspiration (rFNA)
Subjects must have a body mass index (BMI) of 25-40

Subjects must fit into ONE of the following menopausal categories:

Premenopausal (n = 40) - defined as meeting all the following criteria:

Have had at least 8 menstrual cycles in the past 12 months
Have had no hormonal contraception in the past 3 months prior to registration
Have serum hormone parameters (estradiol [E2], progesterone, follicle stimulating hormone [FSH]) in premenopausal range on the day of rFNA; NOTE: subjects will self-report menopausal status at registration, and confirmation of hormonal parameters will occur after registration as part of pre-intervention procedures; if there is mis-assignment of status, the recruitment of future subjects will be adjusted accordingly

Postmenopausal (n = 40) - defined as meeting all of the following criteria:

Last menstrual period (LMP) > 1 year previously
Have had no hormone use in the past 3 months prior to registration
Serum E2, progesterone, FSH in postmenopausal range on the day of rFNA; NOTE: subjects will self-report menopausal status at registration, and confirmation of hormonal parameters will occur after registration as part of pre-intervention procedures; if there is mis-assignment of status, the recruitment of future subjects will be adjusted accordingly
Subjects must have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
Subjects who have been diagnosed with a prior cancer at any site (other than breast cancer) may participate as long as they have been off medical therapy for at least 12 months prior to registration
Subjects with prior breast cancer must be off all systemic therapy (including endocrine agents) for at least 2 years prior to registration
Subjects must be willing to undergo a random fine needle aspiration (rFNA) at the beginning and end of the intervention period
Subjects must be willing and able to abstain from the use of aspirin for at least 2 weeks prior to undergoing each rFNA procedure (pre- and post-intervention)
Subjects must have the ability to understand and the willingness to sign a written informed consent prior to registration on study
Subjects must have a smart phone (newer generation Android or any Iphone) to be able to track their food intake times
Subjects must be willing to restrict food intake to an 8 hour period every day (12 pm to 8 pm)

Exclusion Criteria:

Subjects who have received hormonal contraception and/or hormone therapy in the past 3 months are not eligible
Subjects who are pregnant and/or lactating are not eligible
Subjects who are noted (upon initial online screening) to do 150 minutes or more of moderate level physical activity each week, get less than 8% of their calories from saturated fat, and eat more than 5 fruit and vegetable servings per day will not be eligible
Subjects who are part of any structured weight loss programs (e.g. Weight Watchers, etc.) are not eligible
Subjects who have undergone bariatric surgery are not eligible
Subjects who work night shifts are not eligible
Subjects who have diabetes or uncontrolled hypertension are not eligible; NOTE: for the purposes of this study, uncontrolled will be defined as diastolic pressure over 100 mmHg