Hunger mechanic is a type of "realistic" additions to force the player to ingest specific consumables(i.e. food type items) periodically to avoid dying or losing HP.
Most game don't include such repetitive and boring mechanic, instead making consumables giving bonuses(such as healing).
Types of hunger mechanic:
A.Satiation bar: can be pre-filled by eating in advance. Decreases with effort(running/combat) more rapidly, requiring more consumables.
B.HP drain: simply reduces HP periodically. Healing spells/potions are equally effective as food. Equip items may reduce the effect of hunger.
C.Rest-equals-food: effort(combat/movement) costs specific energy that can be reclaimed by resting(stamina/energy recovery) or eating(energy buff). Discourages prolonged combat.
D.Food-buff: eating food periodically is necessary to get buffs to abilities/skills/combat/stats. Similar to buff-granting potions, except the pre-buff(hunger state) is crippled.(Buff potions are also discouraged in good design, as they create a periodic task that increases routine work)

All of the above are not recommended, regardless of realism required:
Negative periodic bonuses create unnecessary extra routine(return to status quo) to all players(and really don't fit outside of survival games).

Specific arguments for not including these "realistic" mechanics is partial realism and lack of aesthetic relevance to the genre, instead of only hunger, the game must equally include defecation, food poisonings, food-borne illness and related concepts, eventually emulating a medically accurate model of a humanoid being(a simulation genre game with RPG elements).

RPG are instead focused on abstract idea of a character and statistical calculations determining "realism of a scene"(like fantasy novel doesn't focus on routine and mundane, only the important parts), which means emulation of realistic features has to be by mechanical rules and abstract limits set by design(hunger points, all food weights the same, has the same size/content,etc which will appear unrealistic in scope of simulation). Essentially, the more realism you add, it becomes more apparent that realism is missing and complexity grows exponentially until the game can't handle it due resource use.

Realism is the opposite of escapism and forcing players to re-experience/recall reality in any form breaks immersion(and therefore the point of the game), even innocent attempts to follow realistic characters(such as realistic graphical avatars) make players to connect them with real world(making avatar of their photos, their favorite people,etc).