My coworker eats way too much and I'm going to publicly tell them tomorrow.
Why do you want to embarrass them like that?
I think it's gross and I'm sick of it.
If it's bugging you that much then you should let them know but you should do it privately. They might not realize that their eating habits are gross so just be polite about it and let them know. Otherwise, you risk making a scene and hurting their feelings.
I'm not sure if that's true but this is a good opportunity to make a scene.
I do not think that you should make a scene. I think that telling them privately might be helpful because maybe they are not realizing what is going on with their eating habits.