Energy intake and expenditure of free-living, pregnant Colombian women in an urban setting.

BACKGROUND: This study examined the components of energy balance in poor, free-living pregnant women living in an urban setting of a developing country. OBJECTIVES: We tested the following hypotheses: 1) energy intake increases in pregnancy and is greater than when nonpregnant and nonlactating (NPNL), 2) basal metabolic rate (BMR) increases in pregnancy and the increase is positively correlated with prepregnancy fatness, and 3) energy expenditure in activity decreases in pregnancy and is lower than in NPNL women. DESIGN: Pregnant women were studied at 14.8 +/- 3.4 (n = 40), 25.0 +/- 3.2 (n = 54), and 34.9 +/- 2.4 (n = 43) wk gestation, and NPNL women at baseline (n = 114) and at 3 (n = 103) and 6 (n = 93) mo. Energy intake was measured by using estimated diet records and energy expenditure by using the flex heart rate method. Time allocation in physical activity was assessed by observation. RESULTS: In pregnant women, body weight, BMR, and energy intake increased but total daily energy expenditure (TDEE) did not change significantly. There were no significant changes in time allocation to selected activities except for lying down. In comparison with NPNL control subjects, women in late pregnancy had higher energy intakes and BMRs. Values for TDEE were not significantly different, but pregnant women expended less energy in activity and allocated more time to 2 energy-saving activities and less time to 2 energy-demanding activities. CONCLUSION: A decrease in energy expenditure in activity and changes in time allocation are important ways in which pregnant women meet the energy demands of pregnancy.