With, one in three Americans now having a body mass index (BMI) greater than 30, and the fastest growing segment of the population having a BMI greater than 40, it is paramount to conduct validation of approaches to measure body composition. Currently the dual-energy x-ray absorptiometry (iDXA) is the gold standard for measuring the body composition. But it is often difficult to perform since it is limited to specific height, weight and BMI's. InBody is a tool which uses bio electric impedance to measure the body composition. This study will compare both approaches. Validation is necessary as it is clinically quite pertinent to accurately assess a patients' body fat percentage, fat free mass, and total body water and changes that are occurring with nutritional support.

This study will use a stratified design. Eligible participants will be categorized with BMI category to receive InBody followed by iDXA. A total of 176 participants will be placed in 1 of 4 arms (n = 44 per arm) based on their BMI: 1) 18.5-24.9; 2) 25-29.9; 3) 30-34.9; and 4) ≥ 35. Within these arms, the 44 participants will participate in an InBody 770® body composition measure as well as an iDXA body composition measure.

Inclusion Criteria:

• Between 18 and 65 years of age
• Have a Body Mass Index ≥ 18.5 kg/m2

Exclusion Criteria:

• Are not English speaking
• Are younger than 18 years of age
• Weigh more than 450 lbs
• Taller than 6'6" due to size constraints of the iDXA
• Have a pacemaker, defibrillator, artificial lung, artificial heart, electrocardiograph, or nerve simulator
• People having radioactive iodine thyroid treatment.
• People who have had a nuclear medicine study or a barium X-ray within the last 5 days.
• People with large amounts of metal in their bodies.
• People with arthritis of the spine recorded in the medical record.
• Are pregnant

Subjects with a BMI greater than 18.5 and weigh no more than 450 lbs.