title: Field use of D2 18O to measure energy expenditure of soldiers at different energy intakes.
abstract: To test the application of doubly labeled water under adverse field conditions, energy expenditures of 16 special operations soldiers were measured during a 28-day field training exercise. Subjects were matched by fat-free mass and divided equally between an ad libitum ready-to-eat meal diet and a 2,000 kcal/day lightweight ration. Subjects recorded intakes daily, and body composition was measured before and after the exercise. At the beginning of the study, subjects moved to a new northerly location and, therefore, a new water supply. To compensate for this, a group of soldiers who did not receive heavy water was followed to measure isotopic base-line changes. Energy expenditure by doubly labeled water was in agreement with intake/balance (3,400 +/- 260 vs. 3,230 +/- 520 kcal/day). The overall coefficient of variation of energy expenditure by doubly labeled water was half that of intake/balance (7.6 vs. 16.1%). The coefficient of variation of repeat measures with doubly labeled water was 7.3%. Energy expenditure of the ready-to-eat meal group, 3,540 +/- 180 kcal/day, was not significantly different from the lightweight ration group, 3,330 +/- 301 kcal/day. Doubly labeled water was valid under field conditions.
authors.affiliation: Clinical Nutrition Research Unit, University of Chicago, Illinois 60637.
authors.forename: J P
authors.initials: JP
authors.lastname: DeLany
authors.forename: D A
authors.initials: DA
authors.lastname: Schoeller
authors.forename: R W
authors.initials: RW
authors.lastname: Hoyt
authors.forename: E W
authors.initials: EW
authors.lastname: Askew
authors.forename: M A
authors.initials: MA
authors.lastname: Sharp
mesh_terms: D000328:Adult; D001823:Body Composition; D001834:Body Water / Q000378:metabolism; D003903:Deuterium; D002149:Energy Intake; D004734:Energy Metabolism; D005069:Evaluation Studies as Topic; D005526:Food, Formulated; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D008889:Military Personnel; D010103:Oxygen Isotopes
chemical_list: D010103:Oxygen Isotopes; D003903:Deuterium