No idea. If she has had work done then she's kept it simple and not gone overboard, because in some paparazzi pictures she does look more her age, which just endears her to me.
I think her personality helps a lot as well - she seems like someone who you could have a great boozy lunch with and her recipes are generally easy to follow. I like her commitment to saving time by sometimes using ready made stuff!
I met her in person at a signing and she really is lovely.