The sun is bad for you; it can give you cancer. Sunscreen is good for you; it helps block the sun's damaging rays. At least that's what you've probably been told all your life, but it's not as simple as that. Sunlight can also provide many health benefits.
Obviously, there's no substitute for using an SPF lotion that's appropriate for your skin -- liberally, every day (seriously... no skimping!). But bet you didn't know that what you eat can also do a lot to aid your skin in protection from the sun.
If I could go back in a time machine, this is the beauty advice I'd give to my clueless teen self. Until that technology is perfected, all I can do is share my hard-won wisdom with the teens of today. It's meant with love.