pnotequalsnp (1077279) writes "Doug Wallace, PHD UC Irvine, gave a very interesting talk on the role of Mitochondrial DNA (mtDNA) entitled "Human Origins, Aging, Cancer & Degenerative Disease".
One of the interesting conclusions is that aging is correlated to body temperature (or exercise) and overeating. mtDNA produces ATP and heat. In warm blooded humans, typically their mtDNA produces more heat for the body by burning calories. On the other hand, cold blooded humans produce less heat and more ATP to use as energy for the body. Basically, keeping your electron transfer chain oxidized in your mtDNA (by exercising or converting calories to heat) will reduce cancer risk (free radicals produced). If you have a tightly coupled mtDNA (produce less heat and more ATP) and you overeat (meaning more calories), then you will reduce the electron transfer chain within your mtDNA, creating more free radicals, resulting in apotosis (cell suicide) and you will age faster.
In short, calorie restricition will increase lifespan and reduce cancer risk, especially in cold blooded humans.
Click here for a video of the talk"