University of California Professor Michael Rose recently made a fascinating claim: When one reaches the age of 90, his or her body automatically stops aging. Professor Rose's theory operates under the assumption that the natural progression of ageing decelerates once you hit 90. This means that a 91-year-old is just as likely to die tomorrow as a 99-year-old. So, the question naturally arises, how does one reach that milestone? Rose's answer: eat like a caveman.