You can do that, but that's not efficient.
I would suggest to create a refresh method inside your fragment, and that refresh method can update some UI components in your fragment, which is very fast and simple. In your activity onStart(), you can find the fragment (that you instantiated in onCreate) with the fragment manager and call the fragment's refresh. One of the reason is efficiency if you don't need to recreate a fragment, then avoid it. Instantiate new fragment takes time.
Bonus: you can set the criteria in the onStart() to determine if you really need the refresh, ie, it has been refreshed 2 seconds ago, do you really want to refresh again?