The 32-year-old reality TV star only gave birth to her first child, daughter North West less than two weeks ago, but is already on a strict diet and exercise regime.
She is reportedly seeing a personal trainer daily in a bid to shed her pregnancy weight, believed to be 60lbs, before she steps out in public.
A source close to Kim said the bootylicious beauty "wouldn't stop talking about her body in the delivery room" and kept "asking her sisters if she looked smaller and skinnier after giving birth".
The pal added: "Kim is obsessed with getting the baby weight off - and fast.
"She really believes she can lose the first 30 pounds in the first month. She wants to look good in a bikini by the end of the summer.
"She got so big. So now she wants to look as hot as possible."
Despite working with celeb trainer Tracy Anderson throughout her pregnancy, Kim is fearful she will never get back her pre-baby frame.
The insider said: "She's terrified she will never get her body back. Everyone has told her not to stress - that it's about being healthy and having a good mind-set for your baby, not about losing the weight right away.
"But her family knows that at the end of the day, Kim will do what Kim wants."
Another source claimed that Kim is also under pressure to lose the weight from rapper fella Kanye West.
It's believed he wasn't happy with Kim's pregnancy wardrobe after she was ridiculed for a series of fashion errors throughout her pregnancy, including a floral dress which left her compared to Robin Williams character Mrs Doubtfire and a black and white number which saw her mocked on the internet for looking like KILLER WHALE Shamu.
The mate said: "When Kim stacked on the weight, Kanye's vision of her maternity fashion went out the drain. He's not happy about how much weight she gained - and said it's her job to get rid of it quickly."