Energy requirements in the eighth decade of life.
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.
Blanc
Stéphane
S
University of Wisconsin-Madison, WI 53706, USA.
Schoeller
Dale A
DA
Bauer
Douglas
D
Danielson
Michelle E
ME
Tylavsky
Frances
F
Simonsick
Eleanor M
EM
Harris
Tamara B
TB
Kritchevsky
Stephen B
SB
Everhart
James E
JE
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