Can a high fiber diet ease transplant recovery?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * MAIN INCLUSION: Documented informed consent of the participant and/or legally authorized representative * MAIN INCLUSION: Age: ≥ 18 years * Patients ≥ 75 years of age that are otherwise eligible to undergo allogeneic HCT are included * MAIN INCLUSION: Karnofsky performance status ≥ 70% * MAIN INCLUSION: Within healthy BMI range 18-29 at the time of consent * MAIN INCLUSION: Ability to read and understand English for questionnaires * MAIN INCLUSION: Patients receiving myeloablative or reduced intensity conditioning regimens * MAIN INCLUSION: Adequate organ function consistent with institutional standards for HCT * MAIN INCLUSION: Patients must be scheduled to receive HCT within 45 days of consent * MAIN INCLUSION: Women of childbearing potential (WOCBP): negative urine or serum pregnancy test (within 45 days prior to the start of conditioning) * If the urine test is positive or cannot be confirmed as negative, a serum pregnancy test will be required * MAIN INCLUSION: Agreement by females and males of childbearing potential to use an effective method of birth control or abstain from heterosexual activity for the course of the study through at least 6 months post-HCT * Childbearing potential defined as not being surgically sterilized (men and women) or have not been free from menses for \> 1 year (women only) Exclusion Criteria: * MAIN EXCLUSION: Clinically significant uncontrolled illness * MAIN EXCLUSION: Active infection requiring antibiotics * MAIN EXCLUSION: History of chronic gastrointestinal conditions such as inflammatory bowel disease or Crohn's disease * MAIN EXCLUSION: Medical contraindications to incorporating fiber in their diet as determined by the treating physician * MAIN EXCLUSION: Self-reported major dietary restrictions limiting fiber intake * MAIN EXCLUSION: Any other condition that would, in the investigator's judgment, contraindicate the patient's participation in the clinical study due to safety concerns with clinical study procedures * MAIN EXCLUSION: Prospective participants who, in the opinion of the investigator, may not be able to comply with all study procedures (including compliance issues related to feasibility/logistics)