ABSTRACT
<p><b>OBJECTIVE</b>Doubly labeled water (DLW) method is the gold standard for measuring total energy expenditure (TEE). We used this method to measure TEE in Chinese young men.</p><p><b>METHODS</b>Sixteen healthy young men age 23±1 years with body mass index 22.0±1.4 kg/m2 were recruited. TEE was measured by the DLW method, and basal energy expenditure (BEE) was determined by indirect calorimetry. We also conducted 24-h activity, energy balance and factorial approach to estimate energy requirements of the subjects.</p><p><b>RESULTS</b>TEE of subjects by DLW method was 9.45±0.57 MJ/day (2258±180 kcal/day). The 24-h activity was 10.80±0.33 MJ/day (2582±136 kcal/day). The energy requirement, derived from energy balance observations, was 9.93±1.32 MJ/day (2373±315 kcal/day). The BEE of 6.65±0.28 MJ/day (1589±67 kcal/day), calculated by the adjusted Schofield equation, was significantly higher (P<0.001) than that measured by indirect calorimetry, 5.99±0.66 MJ/day (1433±158 kcal/day). The TEE derived from the factorial approach was 10.31±0.43 MJ/day (2463±104 kcal/day).</p><p><b>CONCLUSION</b>The TEE of Chinese young men measured by the DLW method was about 10% lower than the current recommended nutrient intake (RNI), suggesting that the RNI for Chinese men maybe overestimated. Further studies are warranted to determine the value of the estimated energy requirement.</p>
Subject(s)
Humans , Male , Young Adult , Asian People , Energy Metabolism , Physiology , Isotope Labeling , Motor Activity , Physiology , WaterABSTRACT
<p><b>OBJECTIVE</b>To accurately calculate the protein requirements in Chinese young adults using the indicator amino acid oxidation technique.</p><p><b>METHODS</b>Nine women and ten men received a restricted daily level of protein intake (0.75, 0.82, 0.89, 0.97, and 1.05 g/kg), along with L-[1-13C]-leucine. Subjects' protein requirement was determined by a biphasic linear regression crossover analysis of F13CO2 data. In doing so, a breakpoint at the minimal rate of appearance of 13CO2 expiration specific to each level of dietary protein was identified. This trial was registered with the Chinese clinical trial registry as ChiCTR-ONC-11001407.</p><p><b>RESULTS</b>The Estimated Average Requirement (EAR) and the Recommended Nutrient Intake (RNI) of protein for healthy Chinese young adults were determined to be 0.87 and 0.98 g/(kg•d), respectively, based on the indicator amino acid oxidation technique.</p><p><b>CONCLUSION</b>The EAR and RNI of mixed protein are 5% and 16% that are lower than the current proposed EAR and RNI (0.92 and 1.16 g/(kg•d), respectively), as determined by the nitrogen balance method. The respective EAR and RNI recommendations of 0.87 and 0.98 g/(kg•d) of mixed protein are estimated to be reasonable and suitable for Chinese young adults.</p>