Fasting During Neoadjuvant Chemotherapy in Patient With Epithelial Ovarian Cancer

The goal of this clinical trial is to see if timed fasting (periods of time that you don't eat) in participants who are receiving chemotherapy prior to surgery is achievable, safe and can improve quality of life, symptoms and outcomes (results) compared to participants who receive standard dietary recommendations in individuals being treated for epithelial ovarian cancer . The main questions it aims to answer are:

* Is it feasible to use intermittent fasting during neoadjuvant chemotherapy?
* Is it safe to use intermittent fasting during neoadjuvant chemotherapy?
* Do participants find it acceptable to use intermittent fasting during neoadjuvant chemotherapy?

Researchers will compare participants who receive standard dietary recommendations to see which method is more achievable, safe, and able to improve quality of life, symptoms and outcomes.

Participants will:

* Receive either the fasting intervention (schedule of times when you do not eat) or standard diet recommendations for 6-9 weeks prior to your surgery starting with the second cycle of chemotherapy.
* All participants will be asked to complete chemotherapy and surgery, cancer imaging, baseline screening tests, nutritional assessments, food diaries, blood tests, and surveys about wellbeing.
* Participants in the intervention group will be asked to follow a fasting schedule that consists of not eating for 16 hours a day followed by normal eating for the remaining 8 hours of the day for 5 days in a row followed by 2 days of regular eating each week.

The quality of diet can affect the biology of cancer. For example, evidence implies a high fat/ Western diet may impose adverse events on ovarian cancer outcomes, and the potential that the gut microbiome alterations secondary to dietary changes may impact tumor responsiveness to treatment and outcomes. This study seeks to clarify the effect of dietary intervention on the tumor and gut microbiome and ovarian cancer biology. The objectives of this study include:

* Primary: To test the feasibility and safety of IF during neoadjuvant chemotherapy (including effects on body composition)
* Secondary: To measure the effects of IF on participant reported outcomes, chemotherapy toxicity and quality of life.
* Exploratory: To test the effect of IF on pathologic response, systemic inflammatory and immune responses, microbial diversity and metabolic pathway alterations.

Eligibility Criteria:
Inclusion Criteria:

* Age 18 years and above
* Participants with confirmed diagnosis of primary epithelial ovarian cancer (EOC) by internal cytologic or histologic evaluation (including fallopian tube and primary peritoneal cancer)
* Participant who had undergone laparoscopic evaluation or laparotomy for diagnosis but did not proceed with surgical debulking
* Participants with stage III or IV EOC planned to undergo chemotherapy including neoadjuvant chemotherapy
* Participants with recurrent epithelial ovarian cancer who will receive platinum-based chemotherapy
* Any invasive ovarian cancer histology
* Normal cognitive function

Exclusion Criteria:

* Age \<18 years
* Malignant complete or partial bowel obstruction confirmed on imaging.
* Participants unable to provide informed consent.
* BMI \<18
* Participants diagnosed with severe malnutrition as assessed by study dietitian
* Type I diabetes on insulin
* Absence of pretreatment CT abdomen and pelvis imaging or \>4-6 weeks between imaging and cycle 1 of chemotherapy.