Bella Hadid went to lunch at the Beverly Hills Hotel on Monday for her dad's birthday, and she posted a handful of silly Snapchats from the celebration. But what caught our eye was her figure -- and the fact that's she looking a little waify these days!

The 20-year-old model, who is preparing to walk in her very first Victoria’s Secret Fashion Show next month, admits she shed some pounds recently. “I have lost weight and gained weight,” she told People. “My weight fluctuates so much. I really didn’t mean to [lose weight]. Like I want boobs. I want my ass back. But it’s not my fault. My weight fluctuates and so does everybody’s and I think that if people are gonna judge, that’s the worst you can possibly do because everybody is different.”

So what happened? Bells says she “accidentally” slimmed down by sticking to a strict diet and intense workout plan. “I worked out so hard and everybody is like, ‘Oh, she looks so skinny blah, blah, blah,'” she revealed. “But I think that if you just stick to something you can really achieve so much. I’ve been eating hard protein every day, and working out for three hours every day. It’s crazy but I think that you know if you set your mind to something I think you can succeed.”

“I think every single person in the world has insecurities,” she continued. “It’s crazy because I think that when other people look at all of the VS models or all of the girls [who] are walking, they’re like, ‘They’re not human. They don’t have any insecurities.’ But I think every single girl [who’s] going to be walking probably has an insecurity.”

Hers? “I wish my ass was bigger,” she admits. Maybe big sis Gigi can take her out for a burger in NYC...we hear she's quite the fan!