Dear Kathy Kerr, Please share the source of this information. This is one of those juicy little facts that I love to tell mothers about the benefits of breastfeeding - the additional fat is designed as a source of food for the baby. I remember hearing that during lactation is the only time you can actually LOSE fat cells, but I never knew the source of these little gems. I'd love to hear more. Lesley Robinson, IBCLC, LLL Leader Corning, NY