title: Energy requirements in the eighth decade of life.
abstract: BACKGROUND
  Knowledge of energy requirements among relatively healthy elderly is limited.
  
  
  OBJECTIVE
  The objectives of the study were to measure total energy expenditure (TEE)-derived energy requirements in a biracial population of older adults without limitations to daily life and to test these empirical measures against national and international recommendations.
  
  
  METHODS
  TEE (measured by the doubly labeled water method), resting metabolic rate (RMR), activity-related energy expenditure (AEE), and body composition were measured in 288 persons aged 70-79 y selected from the Health, Aging, and Body Composition Study.
  
  
  RESULTS
  TEE was lower in women (approximately 530 kcal/d; P < 0.0001) than in men because of the women's lower RMR and AEE. Fat-free mass explained the sex difference in RMR, but body weight failed to account for the women's lower AEE (approximately 1 kcal x kg(-1) x d(-1); P = 0.007). Blacks had lower TEE than did whites (approximately 100 kcal/d, P = 0.03), and that was explained by blacks' lower RMR. Physical activity level (TEE/RMR) did not differ significantly between sexes and races (1.70 +/- 0.23). The World Health Organization (WHO) recommendations overestimated TEE by 10 +/- 15% (P < 0.0001) in women but not in men, and the dietary reference intakes (DRIs) were accurate to 0 +/- 14% (P = 0.1). Both WHO and DRI recommendations are based on an underestimated physical activity level, and WHO recommendations are based on overestimated RMR.
  
  
  CONCLUSIONS
  This study of well-functioning older adults confirms the racial difference in energy metabolism and supports the use of the 2002 DRIs. Because the DRIs and WHO recommendations underestimated PAL, new predictive equations of energy requirements are proposed.
authors.affiliation: University of Wisconsin-Madison, WI 53706, USA.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Blanc
authors.forename: Dale A
authors.initials: DA
authors.lastname: Schoeller
authors.forename: Douglas
authors.initials: D
authors.lastname: Bauer
authors.forename: Michelle E
authors.initials: ME
authors.lastname: Danielson
authors.forename: Frances
authors.initials: F
authors.lastname: Tylavsky
authors.forename: Eleanor M
authors.initials: EM
authors.lastname: Simonsick
authors.forename: Tamara B
authors.initials: TB
authors.lastname: Harris
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Kritchevsky
authors.forename: James E
authors.initials: JE
authors.lastname: Everhart
mesh_terms: D000368:Aged; D000375:Aging / Q000378:metabolism*; D001481:Basal Metabolism; D044383:Black People; D001823:Body Composition; D004734:Energy Metabolism; D005260:Female; D005853:Geriatrics; D006306:Health Surveys; D006801:Humans; D008297:Male; D009751:Nutritional Requirements; D012737:Sex Factors; D014481:United States; D044465:White People; D001741:Black or African American