This one's going to blow your mind
Today, I came across this video by Veritasium (Invidio.us link) that talked about how aging works, and how to slow (and even reverse) it.
The video's 21 minutes long. I watched through it so that you don't have to, and compiled the following steps to slow aging:
Wear sunscreen, avoid X-Ray, anything that can damage your skin
The idea behind this is that eating less keeps your body uncomfortable, this activates the body's defense mechanism, which causes your DNA to be constantly repaired. Integral DNA = Long Life
Explanation at timestamp 11:40
When you make your heart work hard, the body starts its defense and repairing mechanism, causing all sorts of good stuff
Defense mechanism, blah blah
The video is by a reputable channel, with a (fairly) reputable professor, but use common sense anyway: don't overwork yourself, or starve yourself to death, and please don't sit in the snow or in the furnace!
Cheers!