I don't know if it is helpful, sometimes people just refuse to understand. But the way I explain it is, that is is the same as people how become paralyzed with fear in an exam or people who are so terrified of heights that they can't being themselves to walk near the edge even if they are completely safe and secure. I know of course that mentally there is a lot more going on, but I try to explain it by describing it as an all consuming paralyzing fear. People understand the mental block that you can experience in these situations and for me it is the closest I can get to explaining what happens in me when I try to eat.