title: Determinants of total daily energy expenditure: variability in physical activity.
abstract: Excessive energy intake and/or reduced total daily energy expenditure (TEE) causes obesity. To determine the relationship between obesity and TEE in an obesity-prone population, we measured TEE, 24-h sedentary energy expenditure (SEDEE), and basal metabolic rate (BMR) in 30 Pima Indian men (83.6 +/- 20.0 kg and 31 +/- 9% fat) by the doubly labeled water method and a respiratory chamber. The energy expenditure for physical activity (EEACT) was calculated as TEE - (BMR + 0.1 TEE), where 10% of TEE is an estimate of the thermic effect of food. Fat-free mass was the best single determinant (P < 0.01) of TEE, explaining 48% of its variance. TEE, SEDEE, BMR, and EEACT were 12,010 +/- 2292, 9945 +/- 1559, 7677 +/- 1901, and 3297 +/- 1732 kJ/d, respectively. Because EEACT is dependent on body weight, EEACT/kg body wt (41.7 +/- 23.2 kJ.d-1.kg-1) and TEE/(BMR + 0.1 TEE) (1.39 +/- 0.22) were used as indexes of the level of physical activity. Both indexes correlated negatively with percent body fat (r = -0.56, P < 0.01 and r = -0.42, P < 0.03, respectively). These results suggest that obesity is associated with lower levels of physical activity.
authors.affiliation: Clinical Diabetes and Nutrition Section, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Phoenix, AZ 85016.
authors.forename: R
authors.initials: R
authors.lastname: Rising
authors.forename: I T
authors.initials: IT
authors.lastname: Harper
authors.forename: A M
authors.initials: AM
authors.lastname: Fontvielle
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: D000328:Adult; D000368:Aged; D001481:Basal Metabolism / Q000502:physiology; D001826:Body Fluids / Q000502:physiology; D002151:Calorimetry / Q000379:methods; D017666:Deuterium Oxide; D002149:Energy Intake / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology*; D006801:Humans; D007198:Indians, North American; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000208:ethnology / Q000209:etiology*; D005082:Physical Exertion / Q000502:physiology*; D011446:Prospective Studies
chemical_list: D017666:Deuterium Oxide