Betty White gives her secret for living to 100

Betty White will turn 100 on Jan. 17, and she's feeling pretty good about it.

The "Golden Girls" star told People one of her secrets to aging gracefully has been maintaining her sense of optimism.

Another, she joked, is keeping a special sort of diet: "I try to avoid anything green. I think it's working."

"I'm so lucky to be in such good health and feel so good at this age," she told the magazine. "It's amazing."

As her birthday nears, White has enjoyed spending time at home in Los Angeles, where she plays card games, does crossword puzzles and watches animal documentaries, "Jeopardy!" and golf, according to the magazine. An advocate of animal organizations, White also dedicates time to supporting the Wildlife Learning Center, the Monterey Bay Aquarium and Actors and Others for Animals.

Actor Ted Danson, who works with White in her ocean conservation efforts, told People that White has taught him "how to live."

"It's not like she's just a bubbly, joyful person. She wakes up every day and chooses to be that way," he told the magazine. "I think she leads a very purposeful life."