There has been countless studies into the key to living a long life, but Theresa Rowley, a 104 year old from the States puts her long life down to one unorthodox thing - Diet Coke!
Talking to a local news agency, Theresa admitted she never expected to live as long as she has.
"I'm surprised that I'm 104," she explained. "It just doesn't seem like I should be that old."
"When I was 100, I thought I'd never be 104; I thought I'd pass away by that time but it just didn't happen. Then I turn 101, and nothing happens."
She puts her long life down to one thing, her love of drinking diet Coke!
"I drink it because I like it," she explained.
So while her theory isn't scientific at all, Theresa clearly believes the drink is a big part in her long life!