In general, adding a hunger mechanic is one basic way to increase the feeling of realism in a game. It also has the more "meta" purpose of encouraging player advancement and limiting the time they have to freely explore, which in turn can be used to increase difficulty. Similar implementations of the latter mechanic are sometimes referred to as "hunger clocks." (See The Role of Hunger and the linked article.)
- In Rogue, hunger forced the player to advance, since monsters didn't respawn when staying on one level.
- In NetHack, hunger is another possibility for YASD, forcing players to manage their food supplies carefully.
- Angband, with its non-persistent levels, puts little pressure on finding food to stay alive.
- In Cogmind, the player's core cannot be healed except when entering a new level. Since there can be a virtually infinite supply of enemies, this forces the player to advance lest they be destroyed through attrition.