Rumoured to have put on 40 pounds during her first pregnancy, the 33-year-old singer, who is expecting her first child with fiance Matthew Rutler, is determined to stay fit this time, reported Contactmusic.
"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," a source said.
The singer already has a son Max from previous relationship.
Christina 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.