The study is designed to evaluate how the composition of a participant's body, diagnosed with a brain tumor (glioblastoma multiforme) as determined by bioelectrical impedance analysis can predict the progression and outcomes of disease.

The purpose of this study is to monitor the nutritional status of (Glioblastoma Multiforme)GBM patients for one year. We will look at the relationships between phase angle determined by Bioelectrical Impedance Analysis (BIA), nutrition assessment by Subjective Global Assessment and serum albumin, the type of microbes present in the gut, the participant's DNA information, and tumor progression. We will also compare estimated caloric needs determined by BIA and Harris Benedict Equation to Resting Energy Expenditure from Indirect Calorimetry of the people with GBM and the people without.

Inclusion Criteria:

• Subjects must be at least 19 years of age.
• Subjects must have a histologically confirmed supratentorial grade IV astrocytoma (glioblastoma multiforme).
• Women of childbearing potential must have a negative pregnancy test.

Exclusion Criteria:

• Subjects with implanted pacemakers or defibrillators.
• Subjects who are pregnant.
• Subjects with edema.
• Subjects with an amputated extremity.