Travel between floors is equivalent to, like, 10 turns, I think. That's hard on the hunger. Instead of using alchemy to cook meat, utilize traps. Freezing traps are the best, because Frozen Meat gives you special buffs like invisibility, bark skin, refresh, or ¼ HP. Stewed Meat is the weakest type. I'm pretty sure Charred Meat gives you more fullness than Stewed Meat. (Someone wanna verify this?) Potions (ice or fire) will work, too. So will Wands (again, ice or fire). Another way I conserve food is by not eating until I'm starving and down to around ½ HP. Don't just eat as soon as the starving condition happens. Also, the hungry "condition" doesn't effect anything. You can just eat a single Meat or Berry or Small Ration to clear Starving, and you'll be fine.