The extent to which breastfeeding does or does not increase weight loss has been the topic of numerous posts including one on Baby Gooroo which described the results of a Danish study where researchers attributed 4.4 pounds (2 kg) of postpartum weight loss to exclusive breastfeeding for 6 months.

Dewey in 2004 conducted a review of all available data on the topic and concluded that breastfeeding does enhance the rate of postpartum weight loss, but because the effect is relatively small, it may not be detectable in studies that lack adequate statistical power, have imprecise data on postpartum weight change, or do not account for the exclusivity and/or duration of breastfeeding.

While there are countless reports in the media of women shedding unwanted pounds as a result of breastfeeding, most are anecdotal and not scientific. In addition, there is no data to support the premise that women retain a certain number of pounds until they stop breastfeeding altogether.

Because postpartum weight loss is influenced by numerous variables including body mass index (BMI), pregnancy weight gain, exclusivity and duration of breastfeeding, amount of exercise, and diet, it is difficult to quantify how much weight loss can be attributed to breastfeeding alone. But given the prevalence of obesity, even 4.4 pounds of added weight loss reinforces the long held belief that breastfeeding is good for babies and mothers.