Maternal weight and body fat changes were studied in 56 women from delivery to 6 mo postpartum. Six-month weight losses (p less than 0.01) in exclusively breast-feeding (BF), exclusively formula-feeding (FF), and combination breast- and formula-feeding mothers (CF) were 8.30 +/- 0.74, 8.19 +/- 0.96, and 7.22 +/- 0.74 kg respectively; however, only BF experienced a significant change between 3 and 6 mo. Suprailiac and subscapular skinfold thickness decreased over 6 mo (p less than 0.01) with the suprailiac region reflecting a significant feeding-method effect. Increases in triceps fatfold measurements at 3 mo suggest that a temporary redistribution of body fat occurs as the energy stores of pregnancy are mobilized. Lactating mothers consumed more (p less than 0.01) kilocalories (BF, 2055 +/- 435; CF, 2005 +/- 515) than did nonlactating mothers (FF, 1453 +/- 503). Age, parity, and prepregnancy weight exerted significant covariable effects. Results suggest that lactation does play a role in postpartum weight and body fat loss but that the current RDA may be too high to permit such losses.
Human Nutrition and Food Section, School of Home Economics, Louisiana State University, Baton Rouge 70803-4301.