The Doubly Labeled Water (DLW) Method

Our lab specializes in doubly labeled water (DLW) analysis to measure daily energy expenditure (the total number of calories spent each day) in humans and other primates. The DLW method is the international gold standard for measuring free-living energy expenditure. It is non-invasive, non-restrictive, and safe for participants of all ages. It involves the enrichment and tracking of naturally occurring, stable oxygen (18O) and hydrogen (2H) isotopes in urine.

We perform DLW analysis of urine samples in our lab using a state-of-the-art ABB LWIA-912 cavity enhanced absorption spectroscopy analyzer, equipped with a PAL auto-injector. Our capabilities allow us to be at the leading edge of DLW application in population-based research.

We are contributors to the IAEA DLW Database, and continue to work with this international research team to improve the DLW method and to utilize cross-pupulation DLW data to address global health issues. 


What are advantages of the DLW method for measuring energy expenditure?

The DLW method provides gold-standard measures of total energy expenditure and does not interfere with a participant’s regular daily activity. It is easy to administer with participants of all ages, from infancy to old age. As an added bonus, the DLW method also provides simultaneous measurement of body composition.

What is the burden of the DLW method on participants?

Burden is minimal. Unlike other reliable methods for measuring energy expenditure, the DLW method is non-restrictive and participants can go about their everyday lives during the measurement period. In our lab, participants provide one baseline urine sample and are typically asked to provide five additional urine samples over the 14 days following the DLW dose.

Is the DLW method safe?

The DLW method has been in use with humans since 1982 and has no known physiological effects or safety concerns. The DLW method involves the use of stable (i.e., non-radioactive) oxygen and hydrogen isotopes that occur naturally in drinking water and are already inside the body at low concentrations. To date, the DLW method has been used in hundreds of published studies with newborns, infants, toddlers, children, adolescents, adults, and pregnant and lactating women with no reported adverse effect

How can I explain the DLW dose to children?

One helpful way to explain the DLW dose to children is to compare the isotopes in DLW to four-leaf clovers. Most clovers have three leaves, but some are special (and lucky!) and have four leaves. Both are still clovers though. Water is similar in that while all water is made up of two things called oxygen and hydrogen, some oxygen and hydrogen are rare in nature and are special like four-leaf clovers. The water used in the DLW method is just water (and looks/tastes just like always), but it is different than what you normally drink because it has lots of special oxygen and hydrogen in it. These special parts will help us to figure out how many calories you spend each day and how much food you need to eat to grow big and strong.

Are other resources available for me to learn more about the DLW method?

There are a number of published reviews on the DLW method. These and other information can be found at websites hosted by IAEA (, the Doubly Labeled Water Resource Centre (, and the Cambridge Biomedical Research Center (