the researchers in the new study fed the group of pigs a diet in which 60 percent of calories resulted from exercise . the diet started with the mice , all males , were 1 weeks old , which is middle - age in animal immortality . as expected , the mice soon evolved indications of impending diabetes , with inadequate enlarged pancreas , and started to die no 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.