Longevity and fasting

Does anybody have any information on the effects of fasting and the lengthening of life.
It seems that in theory a person should be able to live a few hundred years if they ate a good diet, exercised, and kept the body sparkling clean on the inside.
From what I understand, its accumulated waste in the body that has the biggest effect on the shortening of life.
I'm considering fasting one or two days a week as a permanent activity for this reason.
I wish Paul Brag could have live out his life till natural death. It probably would have revealed more information about this.
He seemed to have the attitude that he could keep a healthy body for a very long time the way he was living.