In fact, the Project Runway star, 37, says that as women age, bigger is better.
"The ultimate beauty secret for a woman getting older is, Don’t be too thin! It is always better to have a little meat on your bones," Klum tells Self in the December issue.
"When you are just muscle, you end up being gaunt in the face, and that makes you look older by 5 or 10 years."
The model, who recently ended her professional relationship with Victoria's Secret, also says she doesn't sweat growing older – or getting wrinkles. "I don’t have anxiety about it, so I’m not running to get Botox. Maybe that will change, but I don’t think so. I feel comfortable in my skin and comfortable with aging, so I think it’s okay that I get wrinkles."
In the meantime, she says sleep keeps her looking fresh ("I go to bed at 8:30 most nights"), as does self-tanner. "I like how it looks," she says, "but sometimes I leave gold shimmery marks all over!”
Of course, looking beautiful isn't Klum's only focus.
In addition to working on her show and designing a line of active-wear for New Balance, she's also raising four kids with her husband, Seal, 47.
Klum admits it can be overwhelming when Leni, 6, Henry, 5, and Johan, 3, bombard her with questions at the dinner table, or when Lou, 13 months, cries for no apparent reason, but she's found a means to stay calm.
"I take a deep breath and say, 'This is my world,' " she tells the magazine. "It’s a roller coaster. Sometimes you’re on top and everything is fabulous, and sometimes it’s crazy. But it’s what I wanted, and in the end, I love it."
Another sanity-saver? Making lists.
"I’m a big believer in to-do lists," she says. "I make them before bed. I think of five things in the shower, and when I come out, I write them down or I can’t sleep. I have daily lists and big-picture lists. I set goals and get my work done, but I have to plan for fun things, too. I’m always thinking about what will make my family happier."