Energy Expenditure

Metabolic Solutions offers project design assistance and mass spectrometry services to help researchers determine energy expenditure using the doubly labeled water stable isotope method.

Stable isotopes of hydrogen (deuterium oxide) and oxygen (oxygen 18) are routinely used to measure energy expenditure in free-living humans or field metabolic studies in animals. The doubly labeled water method using these isotopes is a form of indirect calorimetry that has been extensively validated in animals and humans. The method is completely safe, requires only periodic sampling of body fluids (plasma, urine, saliva), is non-restrictive, and is ideally suited for measurement of energy expenditure in free-living or hospitalized patients.

A typical energy expenditure study protocol using the doubly labeled water method starts with a baseline urine collection to determine pre-dose values for the hydrogen and oxygen isotopes. The subject is given a single oral bolus dose of heavy water (²H₂¹⁸O). Generally, adults are given a dose consisting of 0.15 g H₂¹⁸O/kg body weight and 0.06 g ²H₂O/kg body weight. Children and neonates are given higher doses per kilogram due to their faster water turnover rates. Please contact us with your questions about DLW dose amounts.

Research, validation studies, procedures and technical information for measuring Energy Expenditure with the doubly labeled water method can be obtained in our technical paper: Energy Expenditure using Doubly Labeled Water.