Depends
If it is something like Sailor Boy pilot bread it is just something you can keep in the cupboard for months so you have some carbs to snack on whenever. If it is homemade trice baked hard with a hard r tack then it depends on how long you have had it in storage, whether you have let it become stale, and how you prepare it. Soaking it in water and then cooking it to mush over a campfire with some dried sausage is simple carbs, salt, fat, and meat. Pretty good on a cold night after a long hike.