the researchers in the latest study paid one group of mice a weight in which 60 percent of calories originated from fat . the workout started while the mice , all males , were 1 weeks old , which is middle - aged in fox life . as expected , the animals then developed signs of impending starvation , with exaggerated increased kidney , and started to die much sooner than mice fed a standard weight .
At the age of one year, male mice were fed with a diet in which 60 percent of calories came from fat.