Loss of the fantasy.

Warning: eating disorder trigger.
When we experience grief over the loss of a person, environment, identity, etc, what we’re often grieving is the loss of the fantasy that whatever it was represented for us.
This was my experience with the loss of what I had come to think of as “the perfect” (aka thinnest) body. When restriction failed me and I gained a lot of weight, I grieved the feeling of being untouchable and forever in control. The numbed out fantasy world that I was floating in evaporated, and I landed flat on my face.
Fantasies are there for a reason. They give us perceived safety from a reality we’d rather not living be in. When the bubble bursts it’s frightening and might feel excruciating, but it’s from there that we are given the opportunity to build a life we won’t need or want to run away from.