Probably the difference is that the sprouted grain is allowed to grow more than the malting process. In malting it is ideal to stop the sprouting right when the "sprout" pokes its head out of the grain.
What makes sprouted grain good (better?) for you by the way?
Spent grain has a decent nutritional value. It has some protein and little sugar. But, maybe what is best for you is the fiber content. The later reason also prevents you from eating much. If you are going to bake bread with it, you don't need all that much, you will have to use essentially just as much flour. The grain just adds fiber/texture. It will also keep in the fridge for a couple days...brew on Saturday, make bread on Sunday.