Iron Homeostasis, Adipose Tissue Lipolysis, and Insulin Resistance in Overweight and Obese Humans

Screening:

If a potential subject meets the eligibility criteria after completing the general pre-screening questionnaire, they will be contacted to set up an in-person screening visit where the comprehensive written informed consent will be obtained. This visit may occur either at the Michigan Clinical Research Unit (MCRU) or at the Substrate Metabolism Laboratory (SML). Subjects will complete health history, food frequency, and physical activity questionnaires. Subjects that meet eligibility requirements and provide written informed consent will have a finger-stick performed for the assessment of hemoglobin concentration. Women with hemoglobin < 13.0 g/dL and men with hemoglobin < 14.0 g/dL will be withdrawn from the study.

Percent body fat will be measured using Dual Energy X-ray Absorptiometry [DEXA]. Women will provide a urine sample for a urine pregnancy test prior to the DEXA scan; if a subject has a positive pregnancy test prior to the DEXA scan, they will be withdrawn. The DEXA body composition assessment test may be performed at the screening visit or scheduled anytime between the screening visit and the baseline trial.

Baseline Trial:

Subjects will be provided general instructions on what to eat in the 3 days leading up to their baseline trial and be required to abstain from planned exercise in the 3 days leading up to the baseline and post-blood donation study trials. They will record their dietary intake during the 3 days leading up to the baseline trial and replicate it during the 3 days prior to the post-blood donation study trial. They will be required to fast the night before the trials starting at 9:00PM.