[jameyc]

A lot of the problem isn't so much the stress in particular, as it is your endocrine system's response to it. You go into fight or flight mode and start pumping out cortisol, and most of the rest of your system goes into standby.

Serious research into it is pretty young, but things like regular exercise can help control the process a bit more. We're starting to find compounds that can reduce cortisol response as well (eg. a couple of cups of black tea a day seems to noticeably reduce it.) As research progresses, we should see more advancement.

In the meantime, most of the 'good for you' stuff tends to reduce the problem. Eat well, exercise, get enough sleep, and so forth. They all work to minimize your body's response to stress. Avoiding stressful situations is ideal, but they aren't the root of the problem as much as cortisol is.