I had just been fighting 4 or 5 zombies. After i killed them my hearts were down to 1/2.
Tried to eat a carrot and nothing happened. Tried eating an apple. nothing. Bread, nothing.
Tried reassigning right-click, nothing.
I can open doors, i can use the bed but i cant eat.
ok, so i just loaded the 1 other 1.16.5 world and had no problem eating. i had 9 hearts and 2 empty turkey legs and it let me eat a steak.
I logged back into the world with the problem and as an experiment and noticing my turkey legs were FULL, i ran [sprinted] around my base til 1 or 2 turkey legs were empty and then it allowed me to eat again.
So even though my hearts were 5/10, my turkey legs were FULL and it wouldnt let me eat.