Credit: Terry Richardson for Harper's Bazaar

For Kim Kardashian, New York was hazardous to her health.

While filming Kourtney & Kim Take New York with her older sis, 31, "I gained like 10 pounds," the reality star, 30, tells the March issue of Harper's Bazaar.

The culprit? No gym time ("I worked out once," she admits) and lots of snacking. "All the papers were like, Kim's pregnant!" says Kardashian, who dresses up as Cleopatra for the issue and even interview's the 1963 film's star, Elizabeth Taylor. "I ate the nuts on the street corner, the hot dogs, the street meat. It was not a joke."

Now the E! star is hard at work trying to regain her healthier habits.

"I'm on a diet," she tells the mag. "I need to be. I love to eat—Kit Kats or cookies-and-cream ice cream. I need sugar like five times a day."

Continues Kardashian, "I'm the first to say I have to work out extra hard, and it's such a struggle for me to eat healthy."

One thing that seems to be coming easily, however, is her foray into music -- she recently filmed her first video with her "good friend" Kanye West.

"I can carry a tune, yeah," she tells the mag. "I have a cute little voice. I talked to people in the business, and they said, 'This is what we do for fun. You go to the movies, you go shopping, why don’t you try what we do?'"