The researchers are doing this study to find out whether a high-fiber plant-based diet (HFPBD) can improve quality of life for people with CH. A HFPBD includes foods that are mainly from plants (for example, fruits,vegetables, nuts, beans, and whole grains). The researchers will measure quality of life by having participants complete questionnaires/surveys.

Inclusion Criteria:

• Patients must have confirmed clonal hematopoiesis via next generation sequencing (NGS) of blood or bone marrow biopsy sample
• Patients with clonal cytopenias of undetermined significance (CCUS) are eligible if a bone marrow biopsy is done to exclude other causes.
• Variant allele frequency must be ≥2% for mutation as measured by (NGS)
• Treatment at MSK or at sites listed below that uses EPIC for electronic medical records and willing to share records with MSK through EPIC's care everywhere or through MSK's shared care network. If not meeting this criterion, decision to allow for participation is per PI discretion.
• Age ≥ 18 years
• BMI ≥25 kg/m^2
• Participant or caregiver must be able to complete surveys and have interest in trying new recipes or cooking.
• Screening 24-hour dietary recall must consume <30 grams dietary fiber per day to be eligible (any one of two 24-hour screening dietary recalls).
• For patients at MSK, require bone marrow biopsy at screening in the past 24 weeks with collection of research biobanking sample. Bone marrow at other sites is optional.

Exclusion Criteria:

• Prior MDS/AML directed therapy
• Chemotherapy, radiation, or immunotherapy within the past year (surgical- resection only or other cancer/precancer on observation is eligible)
• Patients with a concurrent malignancy whose natural history or treatment may compromise completion of this trial are excluded.
• Concurrent pregnancy will make a participant ineligible to participate
• Patients that already follow a minimally processed (whole food) plant-based diet in the last 3 months are not eligible (ovo-lacto-vegetarian or processed junk food vegan diets are eligible).
• Patients on GLP-1 drugs are eligible if it has been started at least 3 months prior to study and on stable dose. If it has been started more recently for diabetes mellitus control but not weight loss they are eligible. If it is medically indicated and started for diabetes mellitus control while on trial they will not be removed/excluded from trial.
• Mental impairment leading to inability to cooperate will lead to exclusion from trial participation.
• If in the opinion of the investigator there maybe any concerns regarding the ability of the patient to complete the study safely or any contraindications.
• Concurrent weight loss or dietary programs will be ineligible if require a specific diet or weight loss supplements.
• Plan for prolonged travel during the study that would preclude adherence to prescribed diet. Willingness to comply during travel is not an exclusion.
• Severe allergy to any legume (such as anaphylactic shock) or allergies to multiple legumes or if cross-contamination is a risk are not eligible.
• Severe allergies such as anaphylactic shock to peanuts and/or tree nuts, such as cashews are not eligible.

Memorial Sloan Kettering Cancer Center supports the international committee of medical journal editors (ICMJE) and the ethical obligation of responsible sharing of data from clinical trials. The protocol summary, a statistical summary, and informed consent form will be made available on clinicaltrials.gov when required as a condition of Federal awards, other agreements supporting the research and/or as otherwise required. Requests for deidentified individual participant data can be made beginning 12 months after publication and for up to 36 months post publication. Deidentified individual participant data reported in the manuscript will be shared under the terms of a Data Use Agreement and may only be used for approved proposals. Requests may be made to: crdatashare@mskcc.org.