title: Energy expenditure is very high in extremely obese women.
abstract: To test the hypothesis that total energy expenditure (TEE) and resting energy expenditure (REE) are low in extremely obese individuals, factors that could contribute to maintenance of excess weight, a cross-sectional study was conducted in 30 weight stable, extremely obese women [BMI (mean +/- SEM) 48.9 +/- 1.7 kg/m(2)]. TEE was measured over 14 d using the doubly labeled water method, REE and the thermic effect of feeding (TEF) were measured using indirect calorimetry, and activity energy expenditure (AEE) was calculated as TEE - (REE + TEF). Body composition was determined using a 3-compartment model. Subjects were divided into tertiles of BMI (37.5-45.0; 45.1-52.0; and 52.1-77.0 kg/m(2)) for data analysis. TEE and REE increased with increasing BMI tertile: TEE, 12.80 +/- 0.5, 14.67 +/- 0.5, and 16.10 +/- 0.9 MJ/d (P < 0.01); REE, 7.87 +/- 0.2, 8.78 +/- 0.3, and 9.94 +/- 0.6 MJ/d (P < 0.001), and these values were 29-38% higher than published means of measured TEE in nonobese individuals. No significant differences were observed among BMI tertiles for AEE, TEF, or physical activity level (PAL = TEE/REE, overall mean 1.64 +/- 0.16). The Harris-Benedict and WHO equations provided the closest estimates of REE (within 3%), whereas the obese-specific equations of Ireton-Jones overpredicted (40%) and Bernstein underpredicted (21%) REE. Extremely obese individuals have high absolute values for TEE and REE, indicating that excess energy intake contributes to the maintenance of excess weight. Standard equations developed for nonobese populations provided the most accurate estimates of REE for the obese individuals studied here. REE was not accurately predicted by equations developed in obese populations.
authors.affiliation: Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA. sai.das@tufts.edu
authors.forename: Sai Krupa
authors.initials: SK
authors.lastname: Das
authors.forename: Edward
authors.initials: E
authors.lastname: Saltzman
authors.forename: Megan A
authors.initials: MA
authors.lastname: McCrory
authors.forename: L K George
authors.initials: LK
authors.lastname: Hsu
authors.forename: Scott A
authors.initials: SA
authors.lastname: Shikora
authors.forename: Gregory
authors.initials: G
authors.lastname: Dolnikowski
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Kehayias
authors.forename: Susan B
authors.initials: SB
authors.lastname: Roberts
mesh_terms: D000328:Adult; D001823:Body Composition; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D008954:Models, Biological; D009767:Obesity, Morbid / Q000378:metabolism* / Q000473:pathology; D012044:Regression Analysis