Hunger is a harmful (negative) status effect in Minecraft Java Edition 1.21.
minecraft:hunger
Give Hunger II for 60 seconds (Java Edition 1.13+; duration in seconds, then amplifier where 0 = level I):
Remove the effect from the nearest player:
Hunger drains your food bar faster, piling on exhaustion until you are starving, and it arrives mostly through suspicious-looking food.
Eating rotten flesh has an 80 percent chance to apply 30 seconds of Hunger, and raw chicken carries a 30 percent chance. Pufferfish adds Hunger to its nasty bundle, and husks infect you when they hit you.
Hunger does not directly hurt you; it accelerates exhaustion so your food bar empties faster, which then stops regeneration and eventually starves you. Rotten flesh remains worth eating in emergencies if you have milk or more food behind it.
The effect ID for Hunger is minecraft:hunger. Java Edition 1.13+ /effect commands use this namespaced form. On Java 1.12.2 and earlier the numerical ID was 17.
Run /effect give @p minecraft:hunger 60 1 to get Hunger II for 60 seconds. The first number is the duration in seconds; the second is the amplifier (0 = level I, 1 = level II). Remove it with /effect clear @p minecraft:hunger.
Hunger is a harmful (negative) status effect in Minecraft Java Edition, based on its registry category (harmful).
Rotten flesh (80 percent chance), raw chicken (30 percent), pufferfish, and husk attacks are the survival sources. The effect makes your hunger bar drain much faster for its duration.
Usually, yes: even with the Hunger chance, rotten flesh restores more hunger than the effect typically costs you. It is a fine emergency food, just keep milk or extra food handy.