Is it true that breastfeeding helps loose weight which one has gained during pregnancy?

I think this varies from mothers to mothers. Most mothers swear that breastfeeding helps them to lose weight as Jamie mentioned it burns calories. But some mummies that I know ended up snacking a lot because breastfeeding makes them hungrier so they'd end up eating more and putting back the calories. For myself personally, I don't breastfeed so my weight was pretty much stagnant until the start of the year when I started putting more serious action into it.