Energy Expenditure

Metabolic Solutions offers project design assistance and stable isotope analysis 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 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 plasma, saliva or 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. Additional samples are collected 1 to 2 weeks later. We offer sensitive methods for measuring deuterium and oxygen-18 levels in plasma, urine or saliva with 15-25 µl of sample. If you are interested in small animal energy expenditure studies, please visit our latest advances.

Please contact us with your questions about DLW protocols or stable isotope analysis of body fluids.

Stable Isotope Analysis Applications

Application Subject Type Reference
Total daily energy expenditure Middle-age women and men Total daily energy expenditure: OPEN Study
Weight loss studies Adults Long-term effects of energy-restricted diets
Total daily energy expenditure Children Energy expenditure predicts changes in body fat in children
Comparisons of food frequency questionnaires Adults Accuracy of dietary assessment methods
Total daily energy expenditure Small animals DLW studies in mice
Field metabolic studies Animals Field metabolic rate and body size

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.