Recent advances from application of doubly labeled water to measurement of human energy expenditure.

The doubly labeled water (DLW) method was developed 50 years ago, but nearly 40 years passed before it became a major tool for human nutrition research. Its use has grown dramatically, however, since the first human applications. The DLW method is now the preferred method for determining energy requirements of healthy and clinical populations. The method has been applied extensively to the study of the growing problem of obesity in order to determine the role of energy expenditure and physical activity in weight control. Finally, DLW has provided a new means of validating methods for assessing dietary intake. The accuracy and noninvasive nature of the DLW method makes it ideal for the study of human energy metabolism.