Postprandial thermogenesis in lactating and non-lactating women from The Gambia.

Postprandial thermogenesis was assessed by indirect calorimetry in 32 Gambian women classified into 3 groups as follows--12 nonpregnant nonlactating and 10 lactating women studied during the dry season and 10 lactating women studied during the rainy season. The test meal consisted of a typical GAmbian breakfast and its energy content corresponded to 30% of the individuals resting metabolic rate (RMR) /24 hours. During the dry season the postprandial thermogenesis of lactating women averaged 6.0 +or- 0.4% of the test meal energy contents was similar to that observed in the nonpregnant nonlactating women studied during the same season (5.8 +or- 0.3%). In contrast the postprandial thermogenesis of lactating women studied during the rainy nutritionally unfavorable season was found to be significantly lower (4.9 +or- 0.5%). There was no significant difference in the pre- and postprandial respiratory quotients among groups. This leads to the conclusion that lactation does not change the thermogenic response to food and that the reduction in postprandial thermogenesis observed among lactating women during the wet season constitutes an adaptive response to energy deficit allowing for a conservation of energy in periods of food restriction. (authors modified)