All I seem to do is eat, drink and restock. Surely a sturdy adventurer can do without a meal longer than anyone else.

You don't die when you become hungry or thirsty. Try seeing how long it takes you to do by not eating/drinking at hero. Bet it's a long time.

You just, get hurt a little bit, by not eating/drinking often. Those injures are just your stomach pains/pangs ;)

You do realize you're usually eating maybe once a day? Imagine if you actually had to eat and drink once every 8 hours.

Don't forget that an average person can survive at least three weeks without food, three days without water. An adventurer who is used to hardships could get by longer.

Sure, it's probably a perception thing, but mine is that I need to eat too often :P.

Live insects and live fish and from a creek I can promise you, that even if you ate until you were full once per three weeks and skipped food the other 20 days you would starve to death.

Water is a little different. You can "fill up" every 3 days or so depending on activity levels, general health and weather.

If your character is under some metabolic spells your hunger thirst rates can be affected.