The doubly labeled water sample will be used to confirm site-specific concordance with the accelerometer measurements and to estimate population mean levels of AEE. Additionally, body composition, dietary intake, fasting glucose, insulin, adiponectin, leptin and ghrelin will be measured. The relationships between calories expended in activity and body composition, dietary intake, glucose, hormones and adipocytokines, both within and between each population using doubly labeled water and accelerometers will be examined. In this longitudinal study, weight will be measured at 12 and 24-months, and AEE by accelerometer will be assessed at enrollment and again at 2-years of follow-up; associations between change in AEE and change in weight will be estimated.