Interestingly (or perhaps not) I actually know a bit about this.
Gladiators (or at least the sucessful ones) were extremely well trained, skillful, strong and quick but also, intentilnally, a little overweight. They ate all that they wanted/reasonably could because a good number of gladatorial matches were what were called blood matches. Very few matches were death matches but sometimes they died during blood matches. A blood match was, in effect, a sort of point scoring match, the idea being to draw blood from your oponent 3 times in order to win. The most skillful gladiators rarely killed by accident but still won their blood matches. Gladiators were overweight because a layer of fat protects all (most) of the important blood vessels, so in effect, they would bleed when cut but would be very unlucky to die from their wounds, they would be mostly superficial where as skinnier combatants would regularly die as a result of such matches, their shallow wounds would damage muscle and major blood vessels rather than blood poor fat.
For my next enthralling lecture I will talk about the mating habits of the patagonian brown snail. :33: