A Natural History Study of Metabolic Sizing in Health and Disease

Study Description: This study will examine the relationships between comprehensively measured resting energy expenditure (REE), body composition, and body surface area (BSA) in a wide range of healthy and diseased individuals. Objectives: Primary Objectives: * To compare estimated and measured BSA. * To determine if measured BSA is associated with REE independent of body composition measures Endpoints: Primary Endpoints: * Mean difference and limits of agreement at baseline between measured BSA and predicted BSA calculated from traditional biometrics such as height and weight. * Increase in R\^2 when measured BSA is added to equations predicting REE.