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.