Advancing the use of energy expenditure assessment through doubly-labelled water: global insights and applications in physical activity research in children and adolescents

The accurate quantification of total energy expenditure (TEE) under free-living conditions remains central to understanding human metabolism, physical activity, and energy balance. The doubly-labelled water (DLW) technique, recognized as the global criterion for measuring free-living TEE, has transformed our capacity to examine metabolic variability across different populations including children. DLW applications further used in validating and recalibrating self-reported energy intake and activity data on a global scale.

Recent studies have extended their scope in establishing a universal predictive equation capable of identifying the errors in self-reported energy intakes, redefining the reference standards for dietary surveillance. Global investigations have also revealed developmental and sex-specific variability in TEE during puberty, underscoring the importance of age- and sex-sensitive calibration when interpreting energy expenditure in children and adolescents. Together, these efforts demonstrate that DLW not only benchmarks energy metabolism but also exposes the biases and limitations inherent in questionnaire- and device-based energy assessment.

Within this global framework, methodological advances have extended to the validation of field tools and the development of population-specific prediction equations in children. Our research in Sri Lanka applied DLW to 11–13-year-old Sri Lankan children to validate subjective (recall questionnaires, activity logs) and objective accelerometers) physical-activity measures. The studies demonstrated that commonly used accelerometer equations derived from Western cohorts systematically misestimated activity energy expenditure, leading to the derivation of a new culturally relevant predictive model that explained over 70% of variance compared to DLW. These further shows that calibration to local body composition and movement patterns significantly improves validity of accelerometer-based PAEE prediction.

These studies highlight how DLW—when integrated with accelerometry, behavioural metrics, and fitness outcomes—enables a multidimensional understanding of physical activity and metabolism across developmental stages and geographical settings. The emerging evidence underscores that precision in measurement is not merely methodological but foundational to shaping global recommendations on physical activity, nutrition, and chronic-disease prevention from the childhood.

As the network of DLW-validated datasets expands, spanning more than 30 countries, the approach continues to refine human energy models and expose cross-cultural heterogeneity in energy balance. The integration of such high-fidelity metabolic data with public-health and behavioural research may lead a step toward evidence-based, global physical-activity and nutrition policies.

Dr. Prasangi Dabare is an academic and senior lecturer in physiotherapy, currently serving as the Head of the Department of Physiotherapy at the Faculty of Allied Health Sciences, General Sir John Kotelawala Defence University, Sri Lanka. With a profound background in both clinical practice and academic research, Dr. Dabare has made significant contributions to the field of physiotherapy, particularly in pediatric and geriatric care, physical activity among children and adolescents, and body composition analysis methods.