If your surgeon is unwilling to commit to a date because "it depends",
as satisfying as it would be to give you an answer, (it really DOES
depend--on both the speed of healing, the size of the graft, whether a
membrane is used or not, and the nature of what you consider a "normal"
diet) I would be only speculating.
    The best general advice I can give to you is that the graft will not be
mature tissue; there is frequently some tissue slough after graft
surgery.  Sliding pellicle or split thickness grafts heal a bit faster
than free gingival grafts.  A larger graft will take longer to heal.
Any infection, or suboptimal oral hygiene will retard healing.
    I doubt very much that you'll need to be on a pureed diet; however I
probably would avoid biting into apples, bagels, etc.--the type of thing
that will put significant stress on new graft.  Of course, if it's a
small graft, it may be possible to avoid disturbing it by biting on the
other side of your mouth.
    Your surgeon's assessment of how well you're healing at 7 and 14 days
will give you much more useful information than any guess I might make
today.

Steve