The workshop will review the technical aspects of indirect calorimetry. There will be sessions on metabolic carts, room calorimetry, and animal calorimetry systems. Topics will include a review and comparison of different gas analyzers, derivation and application of equations for measuring energy expenditure and substrate oxidation, approaches to validation and calibration, design consideration for room calorimeters, and an overview of signal processing approaches. The workshop is open to all – we welcome students, trainees, and experienced investigators. Registration is free and includes a continental breakfast for both days as well as a lunch and reception on the 15th.