Postpartum changes in maternal weight and body fat depots in lactating vs nonlactating women.

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.