Mariah Carey is slim, trim and sporting a bikini on the cover of Shape magazine’s latest issue. The mother of twins Monroe and Moroccan reveals how she’s lost 70 pounds since giving birth nearly one year ago.

“Pregnancy was probably the best and the hardest thing I’ll ever go through,” Mariah Carey admitted to Shape. “I know for a lot of women, it can be wonderful and relatively easy. But for me, it was like ‘Okay, honey, do you have to do everything the hard way?’”

Speaking of her weight gain while pregnant with twins the 42-year-old shared, “Everyone said I was fat, so I did something about it. I put on around 70 lbs., but if you look at photos of me when I was pregnant, you’d say, ‘Wow, she gained 9,000 pounds!’ A lot of it was water weight because I pretty much had head-to-toe edema, which is very painful.”

While nearly half of the weight came off immediately after the twins were born on April 30, 2011, the singer was left with 30 pounds to shed the old fashioned way. “I used to be able to slim down just by exercising more, but that’s changed,” said Mariah Carey, who has signed on as a brand ambassador for Jenny Craig. “Since having the babies, I realize that 90 percent of losing weight is my diet.”

photo: Shape magazine