I watched a television program this week on the Discovery channel re. Roman gladiators; it touched briefly on their diet.  

The night before they went into the arena they feasted on meat, fruit, etc. at a "last meal" type banquet - lots of wine, women and song, but prior to that - in the last part of their training - they were fed exclusively a gruel made of barley and beans.  The purpose of the barley/bean diet was to add a lot of fat on top of their muscle.  The fat served as a protective barrier over their muscle/veins, etc. in case they were sliced up in the arena. 

I had never heard that before, but it seemed interesting to me that they chose barley and beans....the gladiators got some protein but were also able to lay down a lot of fat. 

Kath