The thermic effect of food in normal-weight and overweight pregnant women.
A defective thermic response to food may be an energy-sparing adaptation in both obesity and pregnancy. To evaluate the combined effect of obesity and pregnancy on postprandial thermogenesis, the thermic effect of food was assessed for a 240 min period following a high-carbohydrate meal and a typical mixed meal in nine normal-weight non-pregnant, eight overweight non-pregnant, eight normal-weight pregnant and six overweight pregnant women using indirect calorimetry. A test meal that provided 60% of each subject's measured daily requirement for basal metabolism was used. Pregnant women were studied during weeks 30-35 of gestation. Neither obesity nor pregnancy altered the thermic effect of food, although the response to the mixed meal was greater (P < 0.01) than that to the high-carbohydrate meal in all cases. The mean responses for the high-carbohydrate and mixed meals were 26.9 (SD 6.0) and 30.1 (SD 6.2) % baseline energy expenditure respectively, and 7.4 (SD 1.6) and 8.3 (SD 1.6) % of the meal energy load respectively. Obesity and pregnancy were associated with hyperinsulinaemia (P < 0.005) following both test meals, suggesting that postprandial thermogenesis was not altered by insulin resistance in this group. The incremental glucose response was elevated (P < 0.001) in the pregnant women following both test meals; overweight women tended to have a greater incremental glucose response following the high-carbohydrate meal, but it was not significant (P = 0.065). These results do not provide evidence of an impaired thermic response to food in either overweight or third trimester pregnant women.
Bronstein
M N
MN
Department of Nutritional Sciences, University of California, Berkeley 94720, USA.
Mak
R P
RP
King
J C
JC
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D001833:Body Temperature Regulation / Q000502:physiology*; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D005502:Food; D006801:Humans; D007328:Insulin / Q000097:blood; D009765:Obesity / Q000503:physiopathology*; D011247:Pregnancy / Q000502:physiology*; D011248:Pregnancy Complications / Q000503:physiopathology*
D001786:Blood Glucose; D004040:Dietary Carbohydrates; D007328:Insulin