Biological Hazards

When the PCs are in civilization, they can simply deduct 1 coin per person at the end of the day to buy cheap meals and poor lodging.

Nutrition

Not eating or drinking for a day makes you Exhausted.

This exhaustion only be removed once you have gotten nutrition.

After three days without key nutrition, a PC starts Dying.

Sleep Derivation

After one night without a Long Rest, a PC becomes Exhausted.

For each subsequent day without a Long Rest, the PC must succeed a DC XX Constitution Check or collapse Unconscious, where XX is 15 + the number of days without sleeping.