Intermittent Fasting for Breast Cancer Survivors with Obesity

Not currently recruiting at 1 trial location

Overseen By Liza Wayland

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of Colorado, Denver

Must be taking: Anti-endocrine therapy

Must not be taking: Anti-obesity drugs, Antipsychotics

Disqualifiers: ECOG status 2+, Diabetes, Cardiovascular disease, others

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

Compensation: Varies

Number of Visits: Unknown

Duration: 3 months

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial aims to explore how an intermittent fasting program affects weight loss and physical activity in breast cancer survivors dealing with obesity. Participants will follow a 4:3 intermittent fasting plan, involving three modified fasting days each week, and aim to increase physical activity to 150 minutes per week. This study suits individuals who have completed breast cancer treatment, have a Body Mass Index between 25 and 45, and live or work within 30 miles of the trial location. As an unphased trial, it offers a unique opportunity to contribute to research that could enhance lifestyle interventions for breast cancer survivors.

Will I have to stop taking my current medications?

The trial does not require participants to stop taking their current medications. However, you must not be using medications that significantly impact appetite, weight, or energy metabolism, except for anti-endocrine therapy for breast cancer and standard anti-nausea or anti-diarrhea medications.

What prior data suggests that intermittent fasting is safe for breast cancer survivors with obesity?

Research has shown that intermittent fasting can be safe and beneficial for individuals with obesity and breast cancer. One study found that 5:2 fasting was not only safe during cancer treatment but also helped reduce body fat. Another review supports the idea that intermittent fasting can improve health issues related to obesity, such as weight and heart health. These findings suggest that this type of diet is generally well-tolerated. However, individual experiences can vary, so participants should consult their healthcare provider before joining any study. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about intermittent fasting for breast cancer survivors with obesity because it offers a non-pharmacological approach to weight management, which is particularly appealing for individuals who may already be managing multiple medications. Unlike traditional weight loss methods, such as calorie restriction and exercise, intermittent fasting focuses on when you eat rather than what you eat, potentially making it easier to stick to long-term. This method may also offer added benefits like improved metabolic health and reduced inflammation, which are crucial for cancer survivors.

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

Research has shown that intermittent fasting can help people with obesity lose weight and improve their health. For example, methods like alternate-day fasting (ADF) and the 5:2 diet have led to significant weight loss, sometimes exceeding 5% of body weight. In breast cancer patients, intermittent fasting safely reduced body fat during treatment. It also improved health by lowering cholesterol and insulin levels. This trial will focus on a 3-month integrated behavioral weight loss intervention, emphasizing intermittent fasting. These findings suggest that intermittent fasting might effectively help breast cancer survivors with obesity manage their weight and improve overall health. ^{2 4 6 7 8}

Who Is on the Research Team?

Victoria Catenacci, MD

Principal Investigator

University of Colorado, Denver

Are You a Good Fit for This Trial?

This trial is for adults who have finished breast cancer treatment, are overweight or obese, and want to try a weight loss program. Participants should be willing to follow an intermittent fasting plan with 3 modified fast days per week and increase physical activity.

Inclusion Criteria

Live or work within 30 miles of the Anschutz Health and Wellness Center (AHWC) (exceptions may be made at the discretion of the Study PI on a case-by- case basis for highly motivated subjects)

Obtain a signed medical clearance from their oncologist for participation in the 4:3 IMF dietary intervention and BfitBwell clinical exercise oncology program. (If participants do not currently have an oncologist signed clearance form their PCP will suffice)

We will recruit participants of all races/ethnicities as the scientific objectives of the study are equally important and valid in all races and ethnicities. In the Denver Metro Area, the population distribution is approximately 73% White, 5% African American, 15% Hispanic, 3% Asian and Pacific Islander, 1% Native American and 3% Other. Although a similar distribution is expected in the proposed study, we will work to ensure adequate minority participation of at least 10% African American and 15% Hispanic

Exclusion Criteria

I have diabetes or high blood sugar, but it's well-controlled if I'm on specific medications.

History of clinically diagnosed eating disorders including anorexia nervosa, bulimia, binge eating disorder. Score >20 on the Eating Attitudes Test (EATS-26) or pattern of response on the Questionnaire of Eating and Weight Patterns (QEWP-5) suggestive of possible binge eating disorder or bulimia will require further assessment by the Study MD to determine if it is appropriate for the subject to participate in the study

Current severe depression or history of severe depression within the previous year, based on DSM-IV-TR criteria for Major Depressive Episode or history of other significant psychiatric illness (e.g., psychosis, schizophrenia, mania, bipolar disorder) which in the opinion of the Study PI would interfere with ability to participate in the diet and exercise interventions and provide feedback on the interventions via questionnaires and focus groups

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive a 3-month lifestyle weight loss program focusing on a 4:3 intermittent fasting paradigm and support to increase physical activity

3 months

Weekly check-ins (virtual or in-person)

Follow-up

Participants are monitored for weight maintenance and adherence to lifestyle changes

3 months

Monthly follow-up visits (virtual or in-person)

What Are the Treatments Tested in This Trial?

Interventions

• Intermittent Fasting

Trial Overview The study tests a 16-week weight loss intervention using intermittent fasting (4:3 paradigm) combined with support for increasing exercise to at least 150 minutes weekly. It aims to see how this affects body weight and adherence among participants post-cancer treatment.

How Is the Trial Designed?

Group I: Behavioral Weight Loss Focused on Intermittent Fasting Experimental Treatment 1 Intervention

3-month integrated behavioral weight loss intervention with a dietary focus on intermittent fasting.

Who Is Running the Clinical Trial?

University of Colorado, Denver

Lead Sponsor

Trials

1,842

Recruited

3,028,000+

National Cancer Institute (NCI)

Collaborator

Trials

14,080

Recruited

41,180,000+

National Insitutes of Health

Collaborator

Trials

1

Recruited

40+

Published Research Related to This Trial

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]

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]

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]

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]

Among 2,741 cancer survivors, 13.8% reported practicing weight-loss restrictive diets, with a higher prevalence in women, those who are overweight/obese, and individuals with breast cancer, indicating a significant trend towards dietary control post-diagnosis.

Fasting was practiced by 6.0% of participants, often associated with the belief that it could improve cancer prognosis; however, those receiving nutritional guidance from healthcare professionals were less likely to engage in fasting or restrictive diets, highlighting the importance of professional dietary advice.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Fasting and weight-loss restrictive diet practices among 2,700 cancer survivors: results from the NutriNet-Santé cohort. Fassier, P., Srour, B., Raynard, B., et al.[2019]

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]

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]

In a study of 32 non-obese individuals over 12 weeks, alternate day fasting (ADF) led to a significant weight loss of 5.2 kg (6.5%) and a reduction in fat mass without affecting fat-free mass, indicating its efficacy for weight management.

ADF also improved cardiovascular risk factors, as evidenced by decreased triacylglycerol levels, increased LDL particle size, and changes in adipokine levels, suggesting potential cardio-protective benefits in normal weight and overweight adults.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Alternate day fasting for weight loss in normal weight and overweight subjects: a randomized controlled trial. Varady, KA., Bhutani, S., Klempel, MC., et al.[2021]

Citations

1. link.springer.com link.springer.com/article/10.1007/s44178-023-00058-5

Feasibility and metabolic effects of a 5:2 fasting ... 5:2 fasting is safe and feasible for breast cancer patients during radiotherapy and suitable to significantly reduce fat mass, but beneficial metabolic effects ...

2. 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.

3. jamanetwork.com jamanetwork.com/journals/jamanetworkopen/fullarticle/2787246

Intermittent Fasting and Obesity-Related Health Outcomes MADF and the 5:2 diet were the only IF types that were associated with statistically significant weight loss of more than 5% in adults with ...

4. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC10098946/

A meta‐analysis comparing the effectiveness of alternate day ... ADF/MADF interventions induce a body weight loss ranging from 0.77% to 12.97%, whereas the 5:2 diet resulted in weight loss ranging from 1.70% ...

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

Intermittent fasting and health outcomes: an umbrella ... IF could beneficially affect a range of health outcomes (decreased WC, fat mass, LDL-C, TG, TC, fasting insulin, and SBP; increased HDL-C and FFM) for adults ...

6. 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 ...

7. sciencedirect.com sciencedirect.com/science/article/abs/pii/S0305737224000525

Intermittent fasting and its impact on toxicities, symptoms ... Intermittent fasting is a dietary intervention that is increasingly being tested for positive outcomes in patients receiving cancer treatment. In this review, ...

8. bmj.com bmj.com/content/389/bmj-2024-082007

Intermittent fasting strategies and their effects on body ... The current evidence provides some indication that intermittent fasting diets have similar benefits to continuous energy restriction for weight loss and ...