A Ring of Satiety (rare) can help prevent starvation. The Rogue class also suffers from hunger less than the Mage or Warrior. Likewise, the Warrior will regin a small amount of health when eating (which offsets the need to rest as often).
Otherwise, look for the dew drops that appear when walking through tall grass/mushroom/flower tiles. They will provide a small amount of HP.
An enchanted vampiric weapon will also regain some of your health when you strike with it.
The Mage's subclass: "Warlock" will have his hunger eased slightly, and wounds healed a little, with each enemy killed.
So, there are some ways. Also, it doesn't seem that Hunger causes any negative side effects, so I suggest you wait until you are Starving in order to ration out your food the most effectively. I usually wait until I am around 70% health before consuming the next ration, since being well-fed will replenish that health.
A well of healing will also remove hunger/starving status.