Nearly 60% of pediatric patients diagnosed with cancer develop malnutrition caused by a combination of disease burden, side effects of chemotherapy, and the intensity of cancer treatment. These patients are known to have an increased risk of infection, treatment-related toxicity, inferior clinical outcomes, and increased risk of mortality. Malnutrition may progress to cancer cachexia, characterized by anorexia, increased inflammation, decreased fat, and decreased muscle mass with subsequent weight loss, which is associated with decreased overall survival. The goal of the proposed research is to determine changes in body composition, weight status, and nutritional status between common nutrition interventions including oral nutrition supplements (ONS), appetite stimulants, and enteral nutrition (EN) among pediatric cancer patients. A secondary goal of this research is to utilize the findings to develop clinical nutrition guidelines for this patient population. The specific objective of the research proposed is to solve the lack of evidence to adequately treat nutritional deficits in the pediatric oncology population. Without this data, there is a lack of clinical consistency in the initiation and selection of appropriate nutrition interventions to provide a more definitive pathway of care. This study can help formulate a clinical guideline for this patient population before, during, and after treatment.