The long-term goal of this study is to determine the efficacy of Time Restricted Eating (TRE) for improving metabolic health, preventing cardiometabolic comorbidities, and improving prognosis after endometrial cancer diagnosis. The primary objective of the protocol is to conduct a 16-week randomized dietary crossover study to evaluate the feasibility, fidelity and preliminary acceptability of TRE among endometrial cancer patients, and to provide proof of principle that TRE can improve metabolic health in this population.

Enrollment: The study team will aim to recruit 15 endometrial cancer patients seen at the Huntsman Cancer Hospital Clinics. Consent may be completed via phone/email or in-person with the study clinical coordinator.

Dietary Intervention: Participants who are consented into the study will participate in a 16-week randomized dietary crossover intervention. The dietary intervention includes 5 study visits, and features a baseline visit, 2-week run-in period, 4-week control diet schedule with prepared frozen meals provided to participants, 4-week washout period, and a 6-week, 8 to 10-hour Time Restricted Eating (TRE) protocol (meal provision with 8 to 10-hour eating and 14 to 16-hour fasting periods). Women will be randomized to either control or TRE, then crossover to the other condition. For the control schedule, women will receive frozen lunch and dinner meals and be provided with a standardized breakfast and snacks menu, and there are no restrictions on timing of eating. For the TRE schedule, women will receive prepared frozen lunch and dinner meals as per the control schedule, but will be asked to consume daily meals, snacks, and calorie-containing beverages within an 8 to 10-hour period that fits their schedule. Fasting period will ramp up during the first week (e.g., Days 1-3, 12-14 h per day, Days 4-6, 14-16 h per day, Days 7+, 16 h per day). Women will be asked to schedule the eating period at the same time each day.

Study Visits and Assessments: Women will attend in-person study visits at the Huntsman Cancer Institute Center for Health Outcomes and Population Equity (HOPE).

• Baseline Visit (Visit 1): The clinical coordinator will obtain consent from the participant. Once consented, women will complete questionnaires to capture information on clinical and demographic factors, and chronotype. Height will be measured using stadiometer, weight will be measured using calibrated scales, waist circumference with measuring tape and blood pressure (BP) using an electronic BP monitor. Participants may take home questionnaires, with mailer, to complete at home.
• 2-Week Run-In Period: The purpose of the run-in period is to record women's usual times of eating episodes and appetite while following their habitual diet. Appetite will be measured using the MyCircacianClock (mCC) phone app that has the capability to sample subjects' current behaviors and experiences in real time in their natural environment. Women will complete 3 x 24-hour dietary recalls on non-consecutive days (ASA-24) and a physical activity recall (ACT24 available online or phone app, or via telephone conference with the clinical coordinator). Sleep and activity will also be objectively measured for 7-days using an Actiwatch.
• Visit 2: Women will provide fasting blood and stool samples. Weight, waist circumference and blood pressure will be measured.
• Control OR TRE Schedules: The participants will be expected to follow their randomized schedule for meal timing. During these schedules, for both study groups, participants will record timing of eating episodes daily using the MyCircadianClock app, complete 3 x 24-hour recalls (ASA24), 1 x ACT24 activity recall, and 7-days of sleep/physical activity will be objectively measured via Actiwatch.
• Visit 3: Women will provide fasting blood and stool samples. Weight, waist circumference and blood pressure will be measured.
• 4-Week Washout Period: During the washout period, women can return to their usual lifestyle. Meals will not be provided during this time.
• Visit 4: Visit 4 will include a telephone call only to discuss the next study phase and schedule meal provision.
• Visit 5: Women will provide fasting blood and stool samples. Weight, waist circumference and blood pressure will be measured. An exit interview may occur in person or via phone/video conference to ask questions about how well the intervention was tolerated and allow participants to provide feedback.
• Follow-Up: Approximately 6-months after consent and roughly 10 weeks after the end of the dietary intervention, participants will be asked to complete a follow-up questionnaire.

Inclusion Criteria:

• Females aged 18 years or older
• Diagnosed with endometrial cancer (any stage)
• Clinically overweight or obese (BMI >= 25 kg/m2)
• At least 3 months post-cancer surgery and/or treatment
• Weight stable for 3 months prior to beginning the study (<4kg weight loss/gain)
• Have a cell phone that is able to download a phone App and able to use phone during the day

Exclusion Criteria:

• Persons with special dietary requirements
• Unable to provide informed consent
• Unable to read, write, or fill in questionnaires in English
• Insulin dependent diabetes
• Night shift workers
• Persons not able to use cell phone during day (like for work)