The goal of this research study is to learn if feeding someone after a stem cell transplant is safe and practical.

Primary Objective:

a. To determine the feasibility, acceptability, and safety of NG tube feeding compared with patients not electing NG tube feeding.

Secondary Objectives:

1. Determine the differential effects of enteral feeding versus Parenteral feeding on nutrition, and quality of life.
2. Determine the differential effects of enteral feeding versus parenteral feeding on survival and, medical comorbidities
3. Determine the differential effects of enteral feeding versus parenteral feeding on Fitbit data study for patients co-enrolled in Pediatric Energy Balance Data Repository Protocol PA18-0130.
4. Identify differential effects on microbiome for patients co-enrolled on MDACC protocol 2014-0938 "Longitudinal Biospecimen Acquisition for All Tumor Types And At-Risk Tissue
5. Determine adverse effects of enteral feeding in this population

Inclusion Criteria:

1. Have plans to be admitted or be admitted to an inpatient pediatric or adult ward for the purpose of HSCT.

2. Be greater than 2 years of age and less than 25 years of age at time of study enrollment.

3. Participants > 18 or guardians for participants < 18 are willing and able to give written informed consent and to comply with all of the study activities. Assent is required for children > 7 years old.

   a) Participants must be English, Italian, Chinese/Mandarin, or Spanish speaking

4. Participants will be encouraged to co-enroll on two additional related energy -balance protocols (highly encouraged but not required)

   1. MDACC protocol PA18-0130. This protocol will enable us to track physical activity through their receipt of a Fitbit (Pediatric Energy Balance Data Repository Protocol.) , and
   2. MDACC protocol LAB99-062 "A Study to Collect Peripheral Blood, Tissue, and Bone Marrow samples from Donors and Recipients of blood and marrow transplants for Laboratory Research" which will allow collection of stool for exploration of the effects of feeding on microbiome data specifically.

5. Participants will be asked to consider co-enrollment on Stem Cell Registry study (not required):

   1. PA19-0756: This is a prospective multi-center study to understand the contribution of vascular endothelial dysfunction towards morbidity and mortality among children and adolescents/young adults (AYA) undergoing HCT/CT.

Exclusion Criteria:

1. Patients in whom EN is contraindicated (e.g intestinal ischemia, complete bowel obstruction, or other anatomical obstructive process), or all available routes of EN are contraindicated. Surgical GT placements for the sole purpose of study participation will not be entertained. See Table 1
2. Females who are pregnant. We follow FACT guidelines. Per Foundation for the Accreditation of Cellular Therapy (FACT), female patients must have a negative pregnancy test 7 days prior to bone marrow transplant.