Exactly How Kim Kardashian West Lost 70 Pounds Post-Baby

Plus, the sister she calls her "body icon."

Kim Kardashian West has famously said she's "confident in her bounce back game" in reference to shedding pregnancy weight after delivery—now, she's proving that when it comes to snapping back, no one does it quite like a Kardashian.

After giving birth to her and Kanye West's second child, Saint, in December, the star has lost a remarkable 70 pounds. And she did it the old-fashioned way: By revamping her diet and working out really, really hard.

"I think dieting is so important to weight loss, whereas, I didn't really ever think that before," Kim told PEOPLE"I thought, 'Oh, I can work out, I can just eat whatever I want.' But you have to work out all the time." 

To reach her goal, Kim opted for the Atkins40 plan (consuming a balanced diet of about 1,800 calories a day and limiting carbs) to get back into pre-pregnancy shape. "[I] eat a lot of fish and turkey," Kim said about her new diet. "It's a full modified thing. I worked with [Atkins] in them sending me their snack stuff. And there would be this trail mix with M&M chocolates with peanuts, so there was stuff that makes it [so] you feel like you can live. And [you're] not like super restricted to anything." 

But like most people, Kim occasionally found it tough to stick to the healthy plan—especially once she had already dropped the first 55 pounds. "I started going to Disneyland and taking my kids and eating Churros and all that really crappy stuff that I love, but then you feel so s----- after you eat it, when you've been doing so good," she opened up.

Kim, who's also mom to daughter North, regularly hits the gym before her children rise at 6 a.m., and when she's having trouble staying inspired fitness-wise, she looks to one person: her younger sister, Khloe. 

"[Khloe] does these workouts with these sauna suits underneath," Kim revealed. "And she's just...I've never seen someone so focused. I saw her naked two days ago changing and I was [like], 'Oh, my God. You are my body icon.' She's never been more on fire."