You really are what you eat. The British Journal of Medicine states that a Mediterranean diet keeps people genetically younger, with their cells showing fewer signs of aging. The study was conducted on 5000 nurses over a decade. Specifically, scientists looked at structures called telomeres. These are protective caps at the end of chromosomes that protect our DNA from losing genetic information during cellular division. With each consecutive division, the telomeres shorten. When they reach a critical length, they signal cells to stop dividing, which essentially leads to aging.