I'll define overtraining as "getting weaker because of too much training," whether from too much volume, weight, or attempting to train on too little food, etc.
Every time this topic comes up it seems like people fall into two camps. On one hand, you have the guys who say "yeah overtraining is real but don't worry about it, it's something that only happens to serious hardcore athletes that work out a million times harder than you." The guys saying this, in my experience, are usually pretty big and hormonized.
On the other hand, you have guys saying "overtraining is a huge problem and if you want to be anything as a bodybuilder, you have to be very careful about balancing workload and recovery." Usually these guys seem to be naturals and/or proponents of HIT, or high frequency / low volume styles. One person who says this (not natural, I know) is Dante -- he insists overtraining is the number one problem with bodybuilders.
As an aside, I currently lift 3 times a week in an attempt to maintain while i diet down, and have been doing upper / lower mwf style, feeling pretty run down. I'm thinking about switching back to once a week, three way (still mwf), more traditional bb style routine to see if I can bounce back.
Is overtraining a serious issue, an epidemic, or a nonissue for the average gym rat?