If you want to overcome your fear you need to first understand it’s causes and realize that the fear you are feeling has no justification. If you repeat in your head something like “this feeling has no reason to exists” or “this fear is just a silly creation of my mind” you will eventually stop suffering from that fear.
Either way, if you find yourself “stuck” with a lot of food in front of you, you can just say you are not well on your stomach and that’s it, that’s a perfectly accepted excuse for not eating.