A recent mouse study at the UC Davis School of Veterinary Medicine demonstrated that a high-fat, or ketogenic, diet not only increases longevity, but improves physical strength.
Jon Ramsey, senior author of the article in Cell Metabolism (September 2017), said “We expected some differences, but I was impressed by the magnitude we observed — a 13 percent increase in median life span for the mice on a high-fat versus high-carb diet. In humans, that would be seven to 10 years. But equally important, those mice retained quality of health in later life.”
Source: https://www.ucdavis.edu/news/eat-fat-live-longer
http://www.cell.com/cell-metabolism/fulltext/S1550-4131(17)30490-4