Pregnant Christina Aguilera is trying to stick to a healthy diet because she doesn't want to gain as much weight as she did when she was pregnant with her son Max.

The singer is pregnant with her first child with fiance Matthew Rutler.

Aguilera reportedly gained 40 pounds while expecting her child Max, her six-year-old son with ex-husband Jordan Bratman, so now she is determined not to put on as much weight.

"She is making much better choices and is adamant about staying healthy. She's telling everyone how vibrant and connected to her body she feels," contactmusic.com quoted a source as saying.

Aguilera had shed a lot of weight before getting pregnant and has so far been able to carry on with her healthy eating regime relatively easily.