""I do watch my food. But I've been blessed in that I never had any body issues during pregnancy. I loved being able to eat whatever I wanted and the whole experience of giving life. And I never worried about losing the weight afterwards, because breastfeeding burns all the calories up so fast. Breastfeeding - that's my big slimming secret!"" Actress and mother-of-two Isla Fisher left it up to nature to help her slim down after giving birth to daughters Olive and Elula.