If you want to live to 100, leaving a little bit of food on your plate may be a good idea. Author Dan Buettner, who studies longevity around the world, found that the oldest Japanese people stop eating when they are feeling only about 80% full.
St. Louis University researchers have confirmed that eating less helps you age slower; in a 2008 study they found that limiting calories lowered production of T3, a thyroid hormone that slows metabolism—and speeds up the aging process.
Having satisfying sex two to three times per week can add as many as three years to your life. Getting busy can burn an impressive amount of calories—sometimes as much as running for 30 minutes. (Which would you rather do?)
Regular sex may also lower your blood pressure, improve your sleep, boost your immunity, and protect your heart.
Stay out of the sun
Avoiding too much sun can head off skin cancer, and it can also keep you looking young by preventing wrinkles, fine lines, and saggy skin.
It’s never too early—or too late—to add sunscreen to your daily skin-care regimen (look for an SPF of 30 or higher). And don’t focus only on your face. Sun damage spots and splotches on your chest and neck will also make you appear older.