The researchers in the latest study fed one group of mice a diet in which 60 percent of calories came from fat. The diet started when the mice, all males, were 1 year old, which is middle-age in mouse longevity. As expected, the mice soon developed signs of impending diabetes, with grossly enlarged livers, and started to die much sooner than mice fed 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.