I am not sure what OP had in mind about fasting, but I recall studies done on lab mouse related to this subject. Studies were about increasing average life expectancy. The results were that the only meaningful increase of life span was gained by limiting food ration. I don't think it was fasting, but amount of food consumed does seem to have significant effect. They claimed life expectancy increased up to 30%.
I remember that study. It was the basis of the intermittent fasting/restricted calories movement. Unfortunately they were unable to replicate it when they changed animals (I don't remember if the subsequent study was on primates or humans).
