Let me give you a little anecdotal evidence. At maxed stats, I can kill abyssal demons indefinitely (with a bunyip) with RUNE ARMOR. No sense using Barrows armor here! However, for things like dust devils or nechyrael where multiple monsters may be attacking me due to the use of combat familiars in multicombat, I use barrows to reduce the amount of food I use. If you are using a bunyip and you need food, use better armor. Or more generally, if you need to use food, use better armor.