To implement "debuffs" like illness, poison, etc. The player would need to gather some herbs and prepare a proper medicine to cure it. Otherwise, the player would start losing health/satiety points after some predefined time. Others will reduce health regeneration, movement speed, attack power, etc. The system could be expanded further with an addition of illness "progression". It would be something like illness stages. Some types of illness would progress and transform into more serious ones if not cured in time. The higher stage would be more diffucult to cure.