I think thats correct. The way the system works now, both fire and poison can deal large amounts of damage very quickly.
That needs to be adjusted. keeping in mind that adjustments would also affect our offensive capabilities against the enemies too.
But none if it means the game is too hard or impossible to play.
I wouldnt call eating apples or other food a matter of "knowing before hand". Its a very ordinary feature in the game and every player should try eating some of the food before those sections of the game.
I believe the tutorial specifically tells you to do so?
That can be further emphasized by other character starting a dialogue about eating food items and benefits that brings, instead of just leaving it to overhead text blurb, which can be missed.
