Autophagy is the process by which cells break down damaged components and replace them with newly created ones. The quality and degree of ongoing autophagy - and most importantly autophagy of damaged mitochondria in your cells - appears to be important for longevity. See past posts here at Fight Aging! for example:
- On Autophagy
- Autophagy Required For Calorie Restriction Benefits?
- The Prospects for Enhancing Autophagy to Combat Age-Related Degeneration
- All Roads Lead to Autophagy?
- More Evidence For Autophagy as a Good Thing
Autophagy researchers are amassing a heavy weight of evidence pointing to autophagy as a key process that boosts healthy longevity, most likely by cycling out damaged mitochondria before those damaged mitochondria can replicate to wreck havoc in your tissues.
Scientists generally concur that accumulated damage throughout the body due to free radicals is one important root cause of age-related degeneration - but the devil is in the details. The vast, overwhelming majority of those free radicals are generated by your [mitochondria] as an unavoidable byproduct. The rate of free radical generation increases greatly with age as the [mitochondria] are themselves damaged by the free radicals they created.
Continuing in this vein, a great post over at Ouroboros analyzes research that provides more and better confirmation of the role of autophagy in extending healthy life span through calorie restriction:
Mitochondria are central to many theories of aging because they produce damaging reactive oxygen species (ROS) as a by-product of normal function. Over time, ROS can degrade mitochondrial DNA (mtDNA), interfering with cellular energy production. The cell’s strategy for dealing with this damage is to recycle its mitochondria on a regular basis....
The main result of this paper is that calorie restriction makes mitochondria turn over a substantial 35% faster, at least in mouse liver. This provides another explanation for the recent finding that [calorie restriction] protects mtDNA from age-related damage.
It's worth a few moments to stop and think about the deep biochemical damage your body is accumulating because of the extra calories you consume.