Your body is not “self” in the way this word is used in this sentence. “Self” here refers to a psychological entity which exists in the mind, and only in the mind - it’s your own mental self-image. It’s big, hairy, mostly unconscious and completely illusory, made up, not real. Never was. Letting go of it is painful, but then you will discover your true self which is also no self. Your body will actually be very happy you did and be thankful to you for that. It will become more healthy than ever before. Fear is the only reason it is hard to realize that your notion of self is illusory, there’s a lot of fear in letting it go. But this fear is also, ultimately, an illusion, and once lived through, it does not return. Good luck!