(Bariatric Surgery Patients): - Age: 18 to 65 years at time of consent - BMI: 35-65 kg.m-2 - Scheduled to undergo bariatric surgery at UTMB - All races and ethnic backgrounds - Ability to speak and read English - Subject has provided informed consent in a manner approved by the IRB and is willing and able to comply with the trial procedures.

(Bariatric Surgery Patients): - Fails the medical criteria for bariatric surgery. - Anemia (hematocrit < 33 % or donated blood in the past 12 weeks.) - Recent (5 years or less) history of cancer - Systemic steroids or immunosuppressant use for 8 or more consecutive days in the past 6 months, or any use of anabolic steroids or growth hormones in the same period. - Body mass index < 35 or > 65 kg.m-2. - Acute infectious disease or chronic infection. - Pregnancy or breast-feeding. - Any medical condition that, in the opinion of the investigator, would place the subject at increased risk for participation. - History of prior non-compliance that would, in the opinion of the investigator, make it difficult for the subject to comply with the study procedures or follow the investigator's instructions. - Concurrent participation in another research study. - Use of an investigational agent in the 30 days prior to signing informed consent.