When I first went to my consultation, I was told the same thing and I felt just like you that my world ended. I didn't want to wait 6 months and be on this so called diet with a doctor. Lucky for me my insurance (BCBS of IL ) changed their policy in February and took that off.
But...when I was first told about this, my insurance coordinator actually told me that many will just wirte down a bunch of stuff. I asked her flat out - How many lie on these things? She told me that more than likely, most do. She did see one that did actually write out their exact diet (which was NOT diet food) and they were denied. So, if you have to, eat normally, not execessive to gain any weight, but also document as if you are dieting. You will be fine.
I ended up taking 4 of the 6 months to get everything done and the other 1.5 to fight with my insurance on documents.