Extremely productive company 37signals (authors of Ruby on Rails) have a short but interesting post on workaholism. It seems that workaholics actually create situations that require more work. This makes sense. And there are plenty of opportunities to fabricate more work: focus on small, inconsequential details; say yes to things before you have finished what you are currently working on; have no idea how long it’ll take to finish your current project (this is a big one for programming), etc.
The problem is that many work environments actually encourage people to act the workaholic way (and look busy all the time). If your workplace is one of these, there’s little you can do.
I’m still not seeing any stats that prove that non-workaholics get more done than workaholics though