title: Energy expenditure of Gambian women during peak agricultural activity measured by the doubly-labelled water method.
abstract: The doubly-labelled water (2H218O) method was used to measure total energy expenditure (TEE) in ten non-pregnant, non-lactating (NPNL), six pregnant (P) and fourteen lactating (L) women in a rural Gambian community. Measurements were made on free-living subjects at a period of peak energetic stress when high agricultural work loads coincided with a hungary season to induce moderately severe negative energy balance. TEE averaged 10.42 (SD 2.08) MJ/d, equivalent to 1.95 (SD 0.38) times resting metabolic rate (RMR). The energy cost of physical activity plus thermogenesis, derived as TEE-RMR, averaged 4.94 (SD 1.96) MJ/d. Expressed per kg body-weight (103 kJ/kg per d) this component of expenditure was 2.5 times greater than comparative values from inactive, affluent women studied previously (39 kJ/kg per d). Estimated energy intake (EI) in a subset of the women (n 13) was only 4.80 (SD 1.58) MJ/d, yielding an apparent deficit of 6.08 MJ/d between EI and TEE. Weight changes suggested that endogenous fat oxidation accounted for only about 0.85 MJ/d, leaving an unexplained difference of over 5 MJ/d. Critical analysis of possible errors suggests that the new doubly-labelled water method has provided the most reliable estimates and that the estimates of EI were substantially in error. This finding has important consequences for other food intake studies.
authors.affiliation: MRC Dunn Nutrition Unit, Cambridge.
authors.forename: J
authors.initials: J
authors.lastname: Singh
authors.forename: A M
authors.initials: AM
authors.lastname: Prentice
authors.forename: E
authors.initials: E
authors.lastname: Diaz
authors.forename: W A
authors.initials: WA
authors.lastname: Coward
authors.forename: J
authors.initials: J
authors.lastname: Ashford
authors.forename: M
authors.initials: M
authors.lastname: Sawyer
authors.forename: R G
authors.initials: RG
authors.lastname: Whitehead
mesh_terms: D000328:Adult; D000383:Agriculture; D001823:Body Composition; D001833:Body Temperature Regulation; D003903:Deuterium; D002149:Energy Intake; D004734:Energy Metabolism; D005260:Female; D005714:Gambia; D006801:Humans; D010103:Oxygen Isotopes; D005082:Physical Exertion; D011247:Pregnancy; D012424:Rural Population; D014867:Water / Q000378:metabolism
chemical_list: D010103:Oxygen Isotopes; D014867:Water; D003903:Deuterium