An interesting pitch for the latest research on autophagy and calorie restriction from EurekAlert!: "Cutting calories helps rodents live longer by boosting cells' ability to recycle damaged parts so they can maintain efficient energy production. ... Caloric restriction is a way to extend life in animals. If you give them less food, the stress of this healthy habit actually makes them live longer ... How does it work? During the aging process, free radicals - highly reactive byproducts of our cells' respiration - wreak havoc on our cellular machinery. ... younger cells are adept at reducing, recycling and rebuilding. In this process, damaged mitochondria are quickly swallowed up and degraded. The broken down pieces are then recycled and used to build new mitochondria. However, older cells are less adept at this process, so damaged mitochondria tend to accumulate and contribute to aging. ... The stress of a low-calorie diet was enough to boost cellular cleaning in the hearts of older rats by 120 percent over levels seen in rats that were allowed to eat what they wanted."