The singer was crowned the winner of the first series of The Voice UK on Saturday (June 2), beating Bo Bruce, Vince Kidd and Tyler James.
Mitchell has stated that she is "fairly fit" and does not need to lose weight in order to be a pop star.
"I am happy as I am. Believe it or not I am fairly fit already so I am Okay. I have no plans to change anything at the moment," she is quoted as saying in The Mirror.
"The only thing I want to do is maybe buy some new clothes and some thank you gifts for friends and family."
The 28-year-old added that her mentor Sir Tom Jones helped inspire her to believe that she could win the competition during Saturday's final.
"All Tom kept saying was to go out there and be confident. That was his biggest thing with me, trying to build that up each week.
"I think you need an alter ego on stage. Winning has definitely given me more confidence."
Leanne Mitchell's cover of Whitney Houston's 'Run to You' has been released as her debut single, and currently sits inside the iTunes top 20.
Watch Leanne Mitchell perform during the final below: