Author(s): Singh J, Prentice AM, Diaz E, Coward WA, Ashford J,
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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.
This article was published in Br J Nutr
and referenced in Journal of Obesity & Weight Loss Therapy