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

Objectives: To examine the components of energy balance during lactation in a population of economically disadvantaged women in an urban developing country setting in order to better understand the metabolic response to lactation. Design. Cross-sectional comparison of lactating (LACT) and non-pregnant non-lactating (NPNL) women. Body size and composition were assessed via anthropometry, energy intake was measured using estimated diet records and energy expenditure using indirect calorimetry and the Flex-Heart Rate method. Setting: Low-income neighborhoods of Cali, Colombia. Subjects: Lactating women (n = 15) studied at 2.4 +/- 0.8, 5.5 +/- 0.8 and 8.9 +/- 1.2 months postpartum, and NPNL women (n = 48) studied in three measurement rounds at 0, 3.5 +/- 0.6 and 7.1 +/- 1.0 months. Results: There were no significant differences between LACT and NPNL women in anthropometric dimensions, but LACT women showed decreases in waist-hip ratio, lean body mass and increases in mid-arm circumference and percentage body fat with time. Energy intake was higher in LACT women (P = 0.04), but there were no significant between-group differences in energy expenditure variables. Conclusion: This group of women met the cost of lactation principally via increased energy intake.