yummy stick
(also this doesn't happen on any modded items)
EDIT:
Holding any vanilla item also makes the food bar flash as if you were holding food.

What version are you playing and what version of the mod are you using? Does this happen if you only have AppleSkin installed?

I tested with just AppleSkin installed and it doesn't happen, I should probably check logs.
I'm on 1.16.5 and using appleskin-mc1.16-fabric-1.0.11

Edit: Here's some client logs, I don't really see anything that'd cause it. Or at least understand anything that'd cause it.
https://pastebin.com/sTkPUzyT

Ok I found that it's caused by LatoOrigins-1.16.5-0.7.2
don't know why but i'm honestly okay with not including that mod since nobody in my server uses that race.

If you could try narrowing down which mod is causing this (by gradually adding mods until it happens again), that would be a big help.

This is the third time i've had to do this for a mod and last time it took like 4 hours but ok i'll try.

This is not exactly a bug, since Lato Origins really give most things a FoodComponent:

• https://github.com/Latokike/lato-origins/blob/master/src/main/java/latokike/latoorigins/config/OriginsFood.java
• https://github.com/Latokike/lato-origins/blob/master/src/main/java/latokike/latoorigins/mixin/ItemsMixin.java

Only certain 'origins' can eat certain things, though, so maybe in the future the newly added API (#99) could be used by LatoOrigins to disable rendering the tooltip when the player can't actually eat the item.