I think celebrities have totally different situations than other women. They have people, dieticians, cooks, personal trainers, skin specialists, plastic surgeons ect not to mention they probably have products available to them that we haven't even heard of. It's great that she can look that good after having a baby but everyone is different so you have to work with the body you have.
Maybe when I have kids I need to get people too lol....although I had a personal trainer once and got tired of him...I pretty much knew what I wanted and what I had to do to get it on my own so after a few weeks I just worked out on my own...not to mention he was annoying.