4:3 Intermittent Fasting Intervention in Adults With Breast Cancer and Overweight or Obesity

Eligibility Criteria

• * Eastern Cooperative Oncology Group (ECOG) Performance Status 2 or higher.
• * Actively undergoing chemotherapy, radiation, immunotherapy and/or targeted therapy (other than anti-endocrine therapy) or are within 1 month of completion of chemotherapy, radiation, immunotherapy and/or targeted therapy (other than anti-endocrine therapy) as of the target intervention start date. Exceptions to this 1-month timeframe can be made on a case-by-case basis at the discretion of the PI if patients are tolerating therapy without adverse effects and will have completed treatment prior to the intervention start date.
• * Plans to relocate within the next 12 months.
• * Plans for extended travel (\>2 weeks) within the next 12 months.
• * Major surgery within the past 3 months (including mastectomy or breast reconstruction but not including lumpectomy or other minor surgeries) or planned major surgery (including mastectomy or breast reconstruction) during the timeframe of the 6 month study intervention and follow-up phases.
• * For Females:
• * Currently pregnant or lactating.
• * Pregnant within the past 6 months.
• * Planning to become pregnant in the next 12 months; sexually active women of childbearing potential may be enrolled if they have had a tubal ligation or use a reliable means of contraception.
• * Recent (past 6 months) acute coronary event, unstable angina, coronary revascularization, stroke, pulmonary embolism, or hospitalization for heart failure or cardiac arrythmia.
• * Symptoms suggestive of cardiovascular disease or unstable angina (e.g., chest pain, shortness of breath at rest or with mild exertion, lightheadedness, syncope).
• * Uncontrolled hypertension, defined as diastolic blood pressure \>100 mmHG, systolic blood pressure \>160 mmHG, or resting heart rate \>100 bpm as measured in duplicate on the screening visit after 5 minutes of rest in a seated position.
• * Diabetes (history of type 1 or type 2 diabetes or fasting glucose ≥126 mg/dL or Hemoglobin A1C ≥6.5% as measured on screening labs) unless on metformin or on dipeptidyl peptidase IV (DPP-IV) inhibitor monotherapy and well-controlled with Hemoglobin A1C \<8%.
• * Undiagnosed hypo- or hyper-thyroidism (TSH outside of the normal range as measured on screening labs) or history of uncontrolled thyroid disorder. History of thyroid disease or current thyroid disease treated with a stable medication regimen is acceptable.
• * Stage 4 or 5 chronic kidney disease as assessed by estimated glomerular filtration rate \<30 as measured on screening labs.
• * Triglycerides \>500 mg/dL or LDL cholesterol \>200 mg/dL as measured on screening labs.
• * Serious arrhythmias, including multifocal PVC's, frequent PVC's (defined as 10 or more per min), ventricular tachycardia (defined as runs of 3 or more successive PVC's), or sustained atrial tachyarrhythmia; 2nd or 3rd degree A-V block, known QTc interval \> 480 msec or other significant conduction defects.
• * Clinically significant abnormalities in hematocrit/hemoglobin, white blood cell count, platelets, serum sodium, potassium, or bicarbonate as measured on screening labs or presence or history of other metabolic or chronic health problems which would impact ability to safely participate in a weight loss intervention involving an intermittent energy restricted diet and exercise including significant cardiac valvular disease or heart failure, significant gastrointestinal, pulmonary, renal, musculoskeletal, neurologic, hematologic, orthopedic, or psychiatric disease.
• * Sustained use of prescription or over-the-counter medications known to significantly impact appetite, weight, or energy metabolism (e.g., anti-obesity pharmacotherapy, appetite suppressants, lithium, stimulants, anti-psychotics, tricyclic antidepressants) with the exception of anti-endocrine directed treatment for breast cancer and standard of care anti-emetic or anti-diarrheal agents.
• * Sustained use of systemic glucocorticoids (current or in the past 6 months) unless physiologic replacement therapy for adrenal insufficiency.
• * Previous obesity treatment with metabolic bariatric surgery or weight loss device, except: (1) liposuction and/or abdominoplasty if performed \> 1 year before screening, (2) lap banding if the band has been removed \> 1 year before screening, (3) intragastric balloon if the balloon has been removed \> 1 year before screening (4) duodenal-jejunal bypass sleeve, if the sleeve has been removed \> 1 year before screening or 5) AspireAssist or other endoscopically placed weight loss device if the device has been removed \> 1 year before screening.
• * Nicotine use (current or past 6 months)
• * Current alcohol or substance abuse.
• * 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.
• * Currently participating in or planning to participate in any formal weight loss or physical activity programs or clinical trials over the next 12 months.
• * Previous participation (within the past 3 years) in the Anschutz Health and Wellness Center (AHWC) BfitBwell Oncology Exercise Program (exceptions may be made at the discretion of the study PI).
• * Previous participation (within the past 3 years) in a weight loss, exercise, or nutrition research study (exceptions may be made at the discretion of the study PI).