title: Daily energy expenditure by five-year-old children, measured by doubly labeled water.
abstract: Current recommendations for daily energy requirements in 5-year-old children (90 kcal/kg per day) are based on energy intake associated with normal growth. It is not known, however, how these recommendations compare with total free-living energy expenditure (TEE) and how much of TEE is related to physical activity. The TEE and the resting metabolic rate (RMR) were measured in 28 white children, aged 5 years (15 boys, 13 girls; mean (+/- SD) weight 20.1 +/- 3.4 kg; height 113 +/- 6 cm; fat 20% +/- 5%). The TEE was calculated during a 7-day period from urinary elimination rates of deuterium (2H) and heavy oxygen (18O) by using a modification of the two-point slope-intercept method; RMR was measured by a ventilated-hood indirect calorimeter. Physical activity indexes were also collected from questionnaires completed by the parents. Measured TEE was considerably lower than the recommended dietary allowances (1370 +/- 222 kcal/day vs 1807 +/- 310 kcal/day; p < 0.0001), whereas measured RMR was slightly higher than predicted RMR (1001 +/- 119 kcal/day vs 952 +/- 78 kcal/day; p < 0.001). The energy cost of physical activity accounted for only 16% +/- 7% of TEE. An index of activity, assessed as the difference between the measured TEE and the predicted TEE, correlated positively with past-year sport-leisure activity assessed by questionnaire (r = 0.40; p < 0.05). We conclude that measured TEE in 5-year-old children yields lower values (approximately 400 kcal/day) than current estimates. A minute part of this difference (20 to 30 kcal/day) is related to the changes in energy stores during growth, but most seems due to lower-than-expected levels of physical activity. This might be related to increased television viewing, which replaces activities requiring energy.
authors.affiliation: Clinical Diabetes and Nutrition Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona.
authors.forename: A M
authors.initials: AM
authors.lastname: Fontvieille
authors.forename: I T
authors.initials: IT
authors.lastname: Harper
authors.forename: R T
authors.initials: RT
authors.lastname: Ferraro
authors.forename: M
authors.initials: M
authors.lastname: Spraul
authors.forename: E
authors.initials: E
authors.lastname: Ravussin
mesh_terms: D002153:Calorimetry, Indirect; D002675:Child, Preschool; D003903:Deuterium; D002149:Energy Intake; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D008297:Male; D009751:Nutritional Requirements; D010103:Oxygen Isotopes; D010809:Physical Fitness / Q000502:physiology*; D015203:Reproducibility of Results; D012119:Respiration / Q000502:physiology; D012146:Rest; D013997:Time Factors
chemical_list: D010103:Oxygen Isotopes; D003903:Deuterium