Characters in LOR require food to survive. In LOR, we recommend the GM decide on a case to case basis if food consumed by the players is sufficient or more. The GM decides on a case to case basis if food is sufficient.
In general characters with higher Constitution scored require more food. Requiring 500g + (Constitution score * 100)g worth of food per day.
For every day a character does not eat food they suffer 1 point of exhaustion and after <consitition modifier> amount of days they begin to suffer 2 points of exhaustion instead
For more details in specific cooking mechanics refer to the cooking skill.
Characters need water to survive, requiring 3 liters of water to survive on a normal day. However for each strenous activity, this increases by 1 litre. On hotter weathers, the water needed increases by 1 litre.
Failure to drink sufficient water caused the target to have disadvantage on Fortitude saving throw until the consume sufficient water.