Dimitrios Kambouris/WireImage

An ever-fit Heidi Klum reveals a few of her best-kept beauty secrets to Allure:

"I learned not to go in the sun early on in my career. A tan lasts for a week or two before it fades, and the sun is so damaging—it's not worth it. I put sunscreen on my kids every day before school and before they play outside. They know the routine."

"You have to think about your whole body when you think about aging. In general, you have to be strong—and that starts with nutrition. I have a glass of milk with dinner every night. When I'm pregnant, I drink a liter of whole milk a day—my trainer would say that's crazy, but it works for me."

"I didn't get stretch marks during my pregnancies, and I wasn't even moisturizing myself like a maniac."

What's your "beauty code"? What rules & tips/tricks help you look (and feel!) your best on a daily basis?