Sub Autofit_All_Tables()
Application.ScreenUpdating = False
Dim Tbl As Table
For Each Tbl In ActiveDocument.Tables
  Tbl.AutoFitBehavior (wdAutoFitWindow)
  Tbl.AllowAutoFit = True
Next
Application.ScreenUpdating = True
Application.ScreenRefresh
MsgBox "Done", vbOKOnly
End Sub