mob/var/hunger, thirst
hunger = 100
thirst = 100

obj/food
verbs
Eat(mob/M as mob)
if(M.hunger == 100) M << "Your full."
M.hunger++
del src
obj/drink
verbs
Drink(mob/M as mob)
if(M.thirst == 100) M << "Your not thirsty."
M.thirst++
del src

Now put that inside some loop or action and make it add if they eat, drink, subtract if action required or if on a sleep(100) timer whatever. That should get you headed in the right direction, also you need to add an icon and Get(), Drop() commands to the food and drink.

LJR