As pretty much everyone else has said, CO goes front to back. However if you have a dietary restriction, mention it to the FA during pre-departure beverages. They tend to be pretty good about honoring special requests on-board.

I've also seen, on a couple occasions, where the person at the back of the cabin can't eat/doesn't want the meal left for them. The FA will go back to someone who seemed indifferent about what the ordered and ask if they mind changing. Generally, there's someone on-board who will accommodate the dietary restrictions of another passenger.

Sounds like a big inconvenience, but it really isn't. I've probably seen it less than a half dozen times on a hundred plus flights and its always worked out.