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

Time Restricted Eating During Chemotherapy for Breast Cancer

This study is being done to better understand how time restricted eating (eating all food in an 8 hour window) can help a person receiving chemotherapy treatment for breast cancer, stages I-IV. The aim is to find out if time restricted is feasible and acceptable to individuals starting chemotherapy for breast cancer. We will test 3 different eating window options compared to a control group for 24 weeks.

Study Overview

• Status: Recruiting
• Conditions: Breast Cancer; Breast Neoplasm Female; Breast Cancer Early Stage Breast Cancer (Stage 1-3)
• Intervention / Treatment: Behavioral: Time restricted eating

Detailed Description

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

• Study Type: Interventional
• Enrollment (Estimated): 40
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Kelsey Gabel, RD, PhD; Phone Number: 312-413-8911; Email: kdipma2@uic.edu

Study Locations

• United States
  • Illinois
    • Chicago, Illinois, United States, 60612
      • Recruiting
      • University of Illinois Chicago
      • Contact: Kelsey Gabel, RD, PhD; Phone Number: 312-413-8911; Email: kdipma2@uic.edu
    • Chicago, Illinois, United States, 60611
      • Recruiting
      • Robert H. Lurie Comprehensive Cancer Center
      • Contact: Kelsey Gabel, RD PhD; Phone Number: (312) 413-8911; Email: fastlab@uic.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age 25-99 at time of consent
• English language or Spanish language (based on availability of lab interpreters)
• ECOG 0 or 1
• Breast cancer to meet histologically confirmed Stage I-III or Stage IV with Medical Oncology approval.
• Demonstrates adequate organ function (absolute neutrophil count ≥ 1,500/μL).
• All screening labs to be obtained within 30 days prior to registration.
• Able to provide written informed consent and HIPAA authorization for release of personal health information, via an approved UIC Institutional Review Board (IRB) informed consent form and HIPAA authorization.
• Women of childbearing potential must not be pregnant or breast-feeding. A negative serum or urine pregnancy test is required per institutional practice guidelines.
• As determined at the discretion of the enrolling physician or protocol designee, ability of the subject to understand and comply with study procedures for the entire length of the study.

Exclusion Criteria:

• Women with type 1 or insulin dependent type 2 diabetes
• Women with BMI > 45kg/m2 and < 18.5 kg/m2
• Women who are pregnant or nursing. A negative serum or urine pregnancy test is required per institutional practice guidelines.
• Shift workers
• Women with a history of eating disorders
• Enrolled participants with a significant weight loss or weight gain within 3 months of the study (weight gain or loss >4kg)
• Uncontrolled HIV/AIDS or active viral hepatitis
• Any prior malignancy <5 years, chemotherapy within the last year or concurrent malignancy whose natural history or treatment has the potential to interfere with the safety or efficacy assessment of this investigational regimen, as determined by the treating medical oncologist.
• Breast cancer recurrence classified by the treating medical oncologist
• Any mental or medical condition that prevents the patient from giving informed consent or participating in the trial.
• Other major comorbidity, as determined by study PI
• Illicit drug use within previous 3 months or excessive use of alcohol (i.e., > 2 drinks/day)
• Currently participating in Weight Watcher's or another weight loss program, including weight loss medication such as GLP-1 medications.
• Myocardial infarction
• Congestive heart failure
• Chronic hepatitis
• Cirrhosis
• Chronic pancreatitis
• History of solid organ transplantation

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Standard Care control; Participants assigned to standard care will follow the recommendations by American Association for Cancer Research and the American Cancer Society.
Experimental: 8-h TRE; Participants assigned to this arm will follow the 8-h TRE protocol. Participants will consume food ad libitum (no calorie or food restrictions) during a self-selected 8-h eating window (beginning at 10:00 am, 11:00am, or 12:00 pm) and fasting for 16 hours daily. They will follow this same eating pattern for the length of the intervention. Calorie free drinks such as water, black coffee, and diet soda, are permitted during the fasting period. The eating window will allow for a typical breakfast/lunch/dinner eating pattern.	Behavioral: Time restricted eating; Participants assigned to this arm will follow the 8-h TRE protocol. Participants will consume food ad libitum (no calorie or food restrictions) during a self-selected 8-h eating window (beginning at 10:00 am, 11:00am, or 12:00 pm) and fasting for 16 hours daily. They will follow this same eating pattern for the length of the intervention. Calorie free drinks such as water, black coffee, and diet soda, are permitted during the fasting period. The eating window will allow for a typical breakfast/lunch/dinner eating pattern.; Other Names: TRE

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Recruitment feasibility	women eligible and referred by staff to the research team. We will also track the number of referred women approached (by phone & in person) by our research team for screening/enrollment and the number of women who decline and their reasons for non-enrollment	24 weeks
TRE Acceptibility	attendance at study visits, completeness of data, and overall and treatment specific loss to follow-up/withdrawal will be closely monitored	24 weeks
TRE adherence	Diet adherence will be monitored either by patient reported start and stop times of food intake and diet pattern scoring and will be assessed by the study coordinator with a total score of 7 days per week followed by a post intervention qualitative survey.	24 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in body weight		24 weeks
Change in HbA1c		24 weeks
Fatigue	The Functional assessment of Cancer therapy - fatigue	24 weeks
Treatment related side effects	Patient-Reported Outcomes Version of the Common Terminology Criteria for Adverse Events, PRO-CTCAE	24 weeks
Change in Insulin		24 weeks
Change in glucose		24 weeks
Change in TNF-alpha		24 weeks
Change in fat mass		24 weeks
Change in lean mass		24 weeks
Change in visceral adiposity		24 weeks
Quality of Life	European Organisation for Research and Treatment of Cancer Core Quality of Life questionnaire	24 weeks
Biochmical blood count Safety	CBC	24 weeks

Collaborators and Investigators

• Sponsor: University of Illinois at Chicago

Study record dates

Study Major Dates

• Study Start (Actual): February 1, 2026
• Primary Completion (Estimated): December 31, 2026
• Study Completion (Estimated): December 31, 2026

Study Registration Dates

• First Submitted: January 27, 2026
• First Submitted That Met QC Criteria: January 27, 2026
• First Posted (Actual): February 4, 2026

Study Record Updates

• Last Update Posted (Actual): May 1, 2026
• Last Update Submitted That Met QC Criteria: April 27, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: breast cancer; intermittent fasting; time restricted eating; fasting; chemotherapy initiation
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Behavior; Skin and Connective Tissue Diseases; Feeding Behavior; Breast Neoplasms; Fasting; Intermittent Fasting
• Other Study ID Numbers: Study2021-0974

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No