Intermittent Fasting for Breast Cancer

Overseen By Medical College of Wisconsin Cancer Center Clinical Trials Office

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Medical College of Wisconsin

Must be taking: Adjuvant endocrine therapy

Must not be taking: Ozempic

Disqualifiers: Diabetes, Eating disorders, Cardiac disease, others

Stay on Your Current Meds You can continue your current medications while participating

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: Unknown

20 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores whether intermittent fasting, which involves fasting for about 14 hours at night and eating during a 10-hour window during the day, can be a feasible lifestyle change for people with breast cancer on hormone therapy. The researchers aim to determine if this fasting approach can enhance overall well-being during treatment. Suitable candidates include breast cancer patients with a BMI over 25 who are on hormone therapy and willing to begin intermittent fasting soon after starting treatment. As an unphased trial, this study provides an opportunity to explore a potentially beneficial lifestyle change alongside current treatment.

Will I have to stop taking my current medications?

The trial does not specify if you need to stop taking your current medications. However, if you are on medications that cause dizziness, low blood sugar, or low blood pressure, your eligibility will be evaluated by your doctor.

What prior data suggests that intermittent fasting is safe for breast cancer patients on adjuvant endocrine therapy?

Research has shown that intermittent fasting (IF) can be safe and manageable for people with breast cancer. For example, one review found that fasting helped reduce symptoms like nausea and vomiting during chemotherapy, improved appetite, and reduced tiredness. Another study found that women who fasted for less than 13 hours each night had a higher chance of their breast cancer returning, suggesting that IF might offer some protection. Overall, these findings suggest that intermittent fasting could be a safe option with potential health benefits. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Intermittent fasting is unique because it introduces a lifestyle change rather than a conventional medical treatment for breast cancer. While standard treatments like surgery, chemotherapy, radiation, and hormone therapies directly target cancer cells, intermittent fasting focuses on altering metabolic processes to potentially slow cancer growth and enhance the effectiveness of existing therapies. Researchers are excited about this approach because it could offer a non-invasive, complementary strategy that might improve patients' overall outcomes and quality of life without the side effects typically associated with more aggressive treatments.

What evidence suggests that intermittent fasting might be an effective treatment for breast cancer?

Research has shown that intermittent fasting (IF), which participants in this trial will follow, might improve health for people with breast cancer. One review found that IF could lessen nausea, vomiting, and tiredness during chemotherapy. Another study suggested that fasting for less than 13 hours each night might raise the risk of breast cancer recurrence. Animal studies have also shown that IF could enhance chemotherapy effectiveness and reduce its side effects. Overall, these findings suggest that IF could support better health and treatment outcomes for breast cancer patients. ^{1 2 3 4 6}

Who Is on the Research Team?

Sailaja Kamaraju

Principal Investigator

Medical College of Wisconsin

Are You a Good Fit for This Trial?

This trial is for women over 18 with HR+/HER2- early breast cancer who are starting or already on adjuvant endocrine therapy. They must have a BMI of at least 25 and be willing to follow a specific intermittent fasting schedule. Participants should not be pregnant, breastfeeding, or planning to conceive during the study. Those with certain health conditions like diabetes, eating disorders, or uncontrolled heart disease cannot join.

Inclusion Criteria

You are overweight, with a BMI of 25 or higher.

My doctor has checked my medications for side effects like dizziness or low blood sugar.

Premenopausal woman: Premenopausal is defined as someone who has had menses at any time in the last 12 months. For premenopausal women who are eligible for this trial, the treating physician may choose to monitor ovarian function with laboratory tests e.g., follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol as clinically indicated to assess their menopausal status; Subjects must agree not to conceive throughout the study and must use accepted methods of contraception; Women of childbearing potential must have a negative pregnancy test within seven days of registration and or seven to 10 days prior to starting study treatment; Subjects who have an atypical sleep-wake schedule or different eating schedules are eligible at the discretion of the study investigators and dietitians as long as they agree to nightly fasting; Ability to understand a written informed consent document, and the willingness to sign it

Exclusion Criteria

You work late at night.

My doctor has confirmed I have a serious illness or disease.

I have been on a diet or used medication for weight loss in the past year.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Intermittent Fasting Intervention

Participants adhere to a daily recurring fourteen-hour nightly fasting period for six months while on adjuvant endocrine therapy

6 months

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Intermittent Fasting

Trial Overview The trial is testing if a six-month intermittent fasting program can improve quality of life and reduce inflammation in women undergoing treatment for early-stage breast cancer. It's designed to see if patients can stick to the fasting routine and how it affects their well-being while they're also taking hormone therapy.

How Is the Trial Designed?

Group I: Intermittent Fasting Experimental Treatment 1 Intervention

Enrolled subjects are expected to start the study intervention after completion of definitive therapy and within three months of starting AET.

Who Is Running the Clinical Trial?

Medical College of Wisconsin

Lead Sponsor

Trials

645

Recruited

1,180,000+

Published Research Related to This Trial

In an 8-week study with 59 obese participants, alternate day fasting (ADF) led to a significant weight loss of 4.2%, while only a small percentage reported mild adverse effects like constipation and dizziness.

ADF was associated with improvements in eating disorder symptoms, including a decrease in depression and binge eating, suggesting that it may have beneficial effects on body image and eating behaviors.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety of alternate day fasting and effect on disordered eating behaviors. Hoddy, KK., Kroeger, CM., Trepanowski, JF., et al.[2018]

Intermittent fasting (IF) during chemotherapy for breast cancer patients was found to be feasible and safe, potentially alleviating chemotherapy-induced adverse effects like fatigue and nausea, although the quality of the data was low.

While IF showed some promise in reducing chemotherapy-induced DNA damage and improving glycemic regulation, the review did not find significant benefits on quality of life or tumor recurrence, indicating that more rigorous studies are needed to confirm these effects.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Intermittent Fasting in Breast Cancer: A Systematic Review and Critical Update of Available Studies. Anemoulis, M., Vlastos, A., Kachtsidis, V., et al.[2023]

Intermittent fasting (IF) during chemotherapy for breast cancer patients significantly reduced gastrointestinal toxicity compared to a non-fasting group, suggesting a protective effect of fasting against chemotherapy side effects.

The study, involving 48 HER2-negative breast cancer patients, also indicated that IF improved metabolic profiles, as evidenced by lower insulin levels in the IF group, which may enhance the overall efficacy of chemotherapy.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Intermittent fasting during adjuvant chemotherapy may promote differential stress resistance in breast cancer patients. Omar, EM., Omran, GA., Mustafa, MF., et al.[2022]

Intermittent fasting, particularly alternate-day fasting, has been shown to effectively reduce body weight by approximately 3%-7% and body fat by about 3-5.5 kg over periods of 3 to 12 weeks in various populations, including normal-weight, overweight, and obese individuals.

Whole-day fasting lasting 12 to 24 weeks also leads to significant reductions in body weight (≈3%-9%) and improvements in blood lipids, with total cholesterol decreasing by 5%-20% and triglycerides by 17%-50%.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effects of intermittent fasting on body composition and clinical health markers in humans. Tinsley, GM., La Bounty, PM.[2018]

Modified alternate-day fasting (ADF) significantly reduces cell proliferation rates in various tissues, regardless of whether the diet is low-fat or high-fat, suggesting its potential as a cancer prevention strategy.

In a 4-week study with male mice, both ADF groups showed similar reductions in T-cell proliferation and decreased plasma insulin-like growth factor-1 levels, indicating that ADF can be effective across different dietary fat intakes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Alternate-day fasting reduces global cell proliferation rates independently of dietary fat content in mice. Varady, KA., Roohk, DJ., Bruss, M., et al.[2009]

Fasting may enhance cancer treatment effectiveness and reduce side effects by creating conditions that hinder cancer cell survival and growth, as suggested by emerging evidence.

The review emphasizes the need for an integrated understanding of how fasting interacts with cancer therapies, recommending the combination of prolonged periodic fasting with standard treatments to improve patient outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effect of fasting on cancer: A narrative review of scientific evidence. Tiwari, S., Sapkota, N., Han, Z.[2022]

A pilot study involving 40 women with a history of early-stage breast cancer showed that prolonged overnight fasting (POF) for 13 hours was feasible, with 95% of participants successfully fasting for at least 70% of the study nights.

Participants experienced significant improvements in anxiety, BMI, depression, and fatigue after 12 weeks of fasting, suggesting that POF may be a beneficial nonpharmacological intervention for improving certain health outcomes in breast cancer survivors.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Pilot study to assess prolonged overnight fasting in breast cancer survivors (longfast). O'Donnell, E., Shapiro, Y., Comander, A., et al.[2022]

Preliminary findings indicate that combining intermittent fasting or a fasting-mimicking diet with endocrine therapy may enhance the effectiveness of treatment for hormone receptor-positive breast cancer.

This combination approach could also help in reducing side effects associated with the endocrine therapy, suggesting a potential strategy for improving patient outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Fasting May Complement Endocrine Therapy. [2021]

Habitual continuous energy restriction (CER) has been shown to effectively prevent breast tumor formation in both animal studies and observational studies in women, while intermittent energy restriction (IER) and intermittent fasting (IF) may offer easier and potentially more effective alternatives for weight control and cancer prevention.

Animal studies suggest that IER and IF can reduce mammary tumor formation and may have different mechanisms of action compared to CER, including greater reductions in fat stores and improved insulin sensitivity, but more research is needed to directly compare these methods in humans.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Energy restriction and the prevention of breast cancer. Harvie, M., Howell, A.[2013]

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC9920353/

Intermittent Fasting in Breast Cancer: A Systematic Review ... The authors reported that fasting improved nausea and vomiting, as well as appetite, satiation, and fatigue between chemotherapy sessions. Qualitative study.

2. clinicaltrials.gov clinicaltrials.gov/study/NCT05259410

Time Restricted Eating During Chemotherapy for Breast ... Pre-clinical murine studies report intermittent fasting increases effectiveness of chemotherapy and decreases treatment related adverse events. ... time ...

3. academic.oup.com academic.oup.com/nutritionreviews/article/83/7/e1660/7745808

Clinical Impact of Time-restricted Eating on Cancer Specifically, women who fasted for less than 13 hours per night were at increased risk of breast cancer recurrence compared with women who ...

4. sciencedirect.com sciencedirect.com/science/article/pii/S2589537024000981

Intermittent fasting and health outcomes: an umbrella ... Our findings suggest that IF may have beneficial effects on a range of health outcomes for adults with overweight or obesity, compared to CER or non- ...

5. bmccancer.biomedcentral.com bmccancer.biomedcentral.com/articles/10.1186/s12885-025-13806-9

The effects of intermittent fasting on anthropometric indices ... This study evaluates its impact on patients with gynecological or breast cancer specifically.

6. thelancet.com thelancet.com/journals/eclinm/article/PIIS2589-53702400098-1/fulltext

Intermittent fasting and health outcomes: an umbrella ... Our findings suggest that IF may have beneficial effects on a range of health outcomes for adults with overweight or obesity, compared to CER or ...