Of course they're food!  They are no doubt healthy because they are so fresh.  I used to pick fiddleheads with my grandfather in the spring.  We would also go looking for wild asparagus and giant puffball mushrooms.  The puffballs were my favourite because we would slice them and fry them in butter.  If you were lucky enough to catch a spring smelt run as well, you were in for a gourmet meal!