title: Energy requirements of women of reproductive age.
abstract: BACKGROUND
  The energy requirements of women have been based on total energy expenditure (TEE) derived from the factorial approach or as multiples of basal metabolic rate (BMR).
  
  
  OBJECTIVE
  This study was designed to reevaluate the energy requirements of healthy, moderately active underweight, normal-weight, and overweight women of reproductive age.
  
  
  METHODS
  The energy requirements of 116 women [n = 13 with a low body mass index (BMI), n = 70 with a normal BMI, and n = 33 with a high BMI] were estimated from TEE measured by the doubly labeled water method. Twenty-four-hour EE and BMR were measured by room respiration calorimetry, activity EE was estimated from nonbasal EE as TEE - BMR, and physical activity level was calculated as TEE/BMR. Body composition was derived from a multicomponent model. Fitness, strength, and physical activity level were assessed, and fasting serum indexes were measured.
  
  
  RESULTS
  Energy requirements differed among the low-BMI (8.9 +/- 0.9 MJ/d), normal-BMI (10.1 +/- 1.4 MJ/d), and high-BMI (11.5 +/- 1.9 MJ/d) groups (P = 0.02-0.001, all pairwise comparisons). Major predictors of BMR, 24-h EE, and TEE were weight, height, and body composition; minor predictors were fasting metabolic profile and fitness. Fat-free mass and fat mass accounted for the differences in EE seen between the BMI groups. The mean physical activity level of 1.86 suggested that the multiples of BMR used to estimate energy requirements have been underestimated.
  
  
  CONCLUSIONS
  Recommended energy intakes for healthy, moderately active women of reproductive age living in industrialized societies should be revised on the basis of TEE.
authors.affiliation: US Department of Agriculture/Agricultural Research Service, Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA. nbutte@bcm.tmc.edu
authors.forename: Nancy F
authors.initials: NF
authors.lastname: Butte
authors.forename: Margarita S
authors.initials: MS
authors.lastname: Treuth
authors.forename: Nitesh R
authors.initials: NR
authors.lastname: Mehta
authors.forename: William W
authors.initials: WW
authors.lastname: Wong
authors.forename: Judy M
authors.initials: JM
authors.lastname: Hopkinson
authors.forename: E O'Brian
authors.initials: EO
authors.lastname: Smith
mesh_terms: D000328:Adult; D001481:Basal Metabolism / Q000502:physiology; D001823:Body Composition / Q000502:physiology; D015992:Body Mass Index; D001834:Body Water / Q000378:metabolism; D002153:Calorimetry, Indirect; D003903:Deuterium; D002149:Energy Intake / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology*; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D018482:Muscle, Skeletal / Q000378:metabolism; D009751:Nutritional Requirements; D009765:Obesity / Q000378:metabolism / Q000503:physiopathology*; D010101:Oxygen Consumption; D010809:Physical Fitness / Q000502:physiology; D012098:Reproduction / Q000502:physiology*; D013851:Thinness / Q000378:metabolism / Q000503:physiopathology*
chemical_list: D003903:Deuterium