Jon said on one of those Runaway tour shows he had stopped drinking and he's never had a really poor diet. I read some health magazine interview with him a few years ago and everything that made up his typical diet was what is considered healthy. He gave up smoking years ago. He hasn't eaten red meat since at least 1992.

My guess is that any physical problems go back to chronic pain from all his foot/leg/knee injuries. We all know he's allergic to "earth," and he probably has frequent headaches and problems from that. It's being human. It pretty much sucks to be mortal.