Effect of infant feeding on maternal body composition

BACKGROUND: Women gain total body weight and accrue body fat during pregnancy. Breastfeeding has been suggested as an efficient means of promoting postpartum weight loss due to its high energy cost. We investigated the effect of infant feeding mode on maternal body composition. METHODS: This study evaluated maternal weight and percent body fat changes in exclusively breastfeeding versus mixed feeding mothers during the first 12 weeks postpartum using the BOD POD. Twenty four mothers aged 19 - 42 years were studied. Participants were recruited from Athens-Clarke County and surrounding areas of the State of Georgia, USA. The study was conducted between November 2005 and December 2006. RESULTS: Prepregnancy weight was higher in mixed feeding mothers than in exclusively breastfeeding mothers (68.4 kg vs. 61.4 kg) but the difference was not statistically significant. At 12 weeks postpartum, exclusively breastfeeding mothers had lost more total body weight than mixed feeding mothers (4.41 +/- 4.10 kg versus 2.79 +/- 3.09 kg; p = 0.072). There was no significant difference in fat weight change between the two groups (4.38 +/- 2.06 kg versus 4.17 +/- 2.63 kg). However, mixed feeding mothers lost slightly more percent body fat than exclusively breastfeeding mothers (1.90 +/- 4.18 kg versus 1.71 +/- 3.48 kg), but the difference was not statistically significant. The trend in percent body fat loss was significant among exclusively breastfeeding mothers (p = 0.034) but not mixed feeding mothers (p = 0.081). Exclusively breastfeeding mothers consumed more calories than mixed feeding mothers (1980 +/- 618 kcal versus 1541 +/- 196 kcal p = 0.08). Physical activity levels were, however, higher in mixed feeding mothers than exclusively breastfeeding mothers. CONCLUSION: Our results provide further evidence that exclusive breastfeeding promotes greater weight loss than mixed feeding among mothers even in the early postpartum period. This suggests that there is the need to encourage mothers to exclusively breastfeed as a means of overweight and obesity prevention.