Standardized assessment of energy excretion in healthy adults: a novel methodology.

Background: Accurate monitoring of energy balance is essential for effective weight management, but the role of energy excretion is often neglected.

Objectives: This study aimed to develop and validate a standardized method for assessing energy excretion using dye-labeled meal replacement bars with consistent and stable ingredients.

Methods: We utilized baseline data from a registered cross-over trial involving 12 healthy adults (7 females and 5 males) with a body mass index of 18-25 kg/m. Participants consumed dye-labeled meal replacement bars under a standardized protocol, and their feces and urine were collected for energy measurement using bomb calorimetry. Correlation analysis was conducted to explore associations between these variables.

Results: The total energy excretion rate averaged 10.48% [standard deviation (SD) 2.56%] of energy intake, with fecal and urinary excretion accounting for 7.95% (SD 2.67%) and 2.52% (SD 0.6%), respectively. Significant individual variability was observed, with total energy excretion ranging from 6.34% to 15.07%, resulting in a maximum difference of 209.64 kcal/d. Fecal energy excretion was positively correlated with fecal wet weight and energy density, whereas urinary energy excretion was associated with digestible energy.

Conclusions: This study presents a standardized and efficient methodology for accurately assessing energy excretion using dye-labeled replacement bars. The findings underscore the notable yet variable role of energy excretion in energy balance and suggest that this method could enhance the precision of future energy balance studies.

Registration Number: This study was registered at chictr.org.cn as ChiCTR2000038421.