title: Energy requirements in nonobese men and women: results from CALERIE.
abstract: BACKGROUND
  The energy intake necessary to maintain weight and body composition is called the energy requirement for weight maintenance and can be determined by using the doubly labeled water (DLW) method.
  
  
  OBJECTIVE
  The objective was to determine the energy requirements of nonobese men and women in the Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy 2 study.
  
  
  METHODS
  Energy requirements were determined for 217 healthy, weight-stable men and women [aged >21 to <50 y; 70% female, 77% white; body mass index (BMI; in kg/m(2)) 22 to <28; 52% overweight] over 28 d with 2 consecutive 14-d DLW assessments in addition to serial measures of body weight and fat-free mass and fat mass by dual-energy X-ray absorptiometry. Energy intake and physical activity were also estimated by self-report over ≥6 consecutive d in each DLW period.
  
  
  RESULTS
  Total daily energy expenditure (TDEE) was consistent between the 2 DLW studies (TDEE1: 2422 ± 404 kcal/d; TDEE2: 2465 ± 408 kcal/d; intraclass correlation coefficient = 0.90) with a mean TDEE of 2443 ± 397 kcal/d that was, on average, 20% (580 kcal/d) higher in men than in women (P < 0.0001). The regression equation relating mean TDEE to demographics and weight was as follows: TDEE (kcal/d) = 1279 + 18.3 (weight, kg) + 2.3 (age, y) - 338 (sex: 1 = female, 0 = male); R(2) = 0.57. When body composition was included, TDEE (kcal/d) = 454 + 38.7 (fat-free mass, kg) - 5.4 (fat mass, kg) + 4.7 (age in y) + 103 (sex: 1 = female, 0 = male); R(2) = 0.65. Individuals significantly underreported energy intake (350 kcal/d; 15%), and underreporting by overweight individuals (~400 kcal/d; 16%) was greater (P < 0.001) than that of normal-weight individuals (~270 kcal/d; 12%). Estimates of TDEE from a 7-d physical activity recall and measured resting metabolic rate also suggested that individuals significantly underreported physical activity (~400 kcal/d; 17%; P < 0.0001).
  
  
  CONCLUSIONS
  These new equations derived over 1 mo during weight stability can be used to estimate the free-living caloric requirements of nonobese adults. This trial was registered at clinicaltrials.gov as NCT00427193.
authors.affiliation: Pennington Biomedical Research Center, Baton Rouge, LA (LMR, CKM, and ER); the Duke Clinical Research Institute and Duke University Medical Center, Durham, NC (WEK and MB); the USDA Jean Mayer Human Nutrition Research Center on Aging at Tufts University, Boston, MA (SKD and SB Roberts); the Department of Medicine, Washington University School of Medicine, St Louis, MO (SB Racette and LF); the Department of Medicine, Salerno University Medical School, Salerno, Italy (LF); CEINGE Biotecnologie Avanzate, Napoli, Italy (LF); and the USDA/Agricultural Research Service, Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX (WWW).
authors.forename: Leanne M
authors.initials: LM
authors.lastname: Redman
authors.forename: William E
authors.initials: WE
authors.lastname: Kraus
authors.forename: Manju
authors.initials: M
authors.lastname: Bhapkar
authors.forename: Sai Krupa
authors.initials: SK
authors.lastname: Das
authors.forename: Susan B
authors.initials: SB
authors.lastname: Racette
authors.forename: Corby K
authors.initials: CK
authors.lastname: Martin
authors.forename: Luigi
authors.initials: L
authors.lastname: Fontana
authors.forename: William W
authors.initials: WW
authors.lastname: Wong
authors.forename: Susan B
authors.initials: SB
authors.lastname: Roberts
authors.forename: Eric
authors.initials: E
authors.lastname: Ravussin
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D001481:Basal Metabolism; D001823:Body Composition; D015992:Body Mass Index; D001835:Body Weight; D004032:Diet; D002149:Energy Intake; D005260:Female; D006801:Humans; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D009751:Nutritional Requirements; D050177:Overweight / Q000378:metabolism / Q000517:prevention & control*; D055815:Young Adult