If poison is in the negatives that means you are poisoned, if it isn't in the negatives then you are safe. if food=0 then health will decrease by -1. Make sure you click the green flag 2 or 3 times because this game does have some glitches, to be honest. Portals lead to different rooms.
DO not eat more than your food limit. Also Can you please review the note on the inside on the sprite Panda.