Want a body like Heidi Klum's? Apparently, the key is to have a bunch of rambunctious kids to chase after. 

The model and Project Runway star says she stays fit by keeping up with her four children, according to People.

"It's very hard to find time obviously to work out," says the 39-year-old, who split from husband Seal last year. "I'm like a mom and dad in one."  

Heidi — who joins the judging panel on America's Got Talent this season  says she squeezes in a little cardio whenever she can.

"When I go shopping, I put on my sneakers and my [fitness] clothes," she admits. "I run through the store, or I take the dogs and the children and I go up the canyon, or I go into the backyard and I jump with my kids on the trampoline  so I try to put the exercise into my daily routine." 

As far as her eating habits, Heidi says she tries to cook healthy at home, and she doesn't indulge in the pizza and pasta that her kids will order when they dine out.

"I have never really dieted," Heidi says, explaining that she pays attention to what she eats. "You have to really look into it and understand it and understand food and what it does for your body and what it needs and doesn't."  

Whatever she's doing, we'd say it's working!

Source: People