the researchers in the latest study fed some group of mice a diet in which 60 percent of calories came from diabetes . the diet started during the researchers , all males , were 1 year age , which is middle - adult in their longevity . as expected , the mice soon developed traces of impending mortality , with grossly enlarged livers , and started to die somewhat sooner than individuals on a standard diet .
At the age of one year, male mice were fed with a diet in which 60 percent of calories came from fat.