Do you really want to lose fields, tables and graphics by pasting as plain text?
Perhaps another 'less destructive' way would be to remove formatting from the selection and insert text before and after it.
Code:
Sub Macro1()
With Selection
.ParagraphFormat.Reset
.Font.Reset
.Range.Style = ActiveDocument.Styles(wdStyleNormal)
.InsertAfter "}}"
.InsertBefore "{{c1::"
End With
End Sub