I'm mad that my coworkers fat shame me but deep down I like it but I can't tell them that.
Why do you like being fat shamed?
Obviously I am not that fat but my coworkers always make jokes about my girth.
If this is what you like then there isn't a problem. If it becomes a problem then you should tell them to stop.
That's never going to happen.
Alright then, it can be your little secret that you actually enjoy all of this. It could be very fun for you and enjoyable, but don't you think it can make others around you uncomfortable? How about still trying to ask them to tone it down for their sake?