UGH! This advice is coming out of the stone ages of dog training. Kind of like you should beat your kid if they forget to take their shoes off and get mud on the carpet. The dog is a PUPPY. If you treat him using the advice above you are likely to cause more behavioral problems and although he may fear you, he will not respect or trust you. If you train a growl out of dog you may very well end up with a dog who bites without warning. There are so many other ways to train that are far more effective and not dangerous for the dog or the handler.You should add NLIY, nothing in life is yours (his).
You need to pin (alpha roll) your dog ASAP.
Who's the boss, anyway? Your dog should NEVER growl at you, it should not enter his mind.
At 8 months you have a big dog with a puppy's brain and he is beginning to assert himself.
You can't allow him to dictate to you for ANYTHING.
To the OP: You need to step up your leadership role with your puppy. Try to get away from applying labels (like aggression and dominance) to normal puppy behavior. I agree with increasing exercise, real attention and short training sessions and using NILIF.
Work on establishing yourself and others in your household as consistent, kind and fair leaders. As mentioned above, dropping delicious things in his bowl while he's eating or trading up while he's eating something he likes (so trade sandwich meat or real chicken for the bone) will create a positive association with you around his stuff. And he'll know he doesn't have to be afraid of you taking something away from him so he'll have no reason to guard it.
Just a quick story: When I adopted Rafi he would jump in my face and snap when he got excited. When we went for a walk he would grab the leash and pull me down the street and all over the place. He would go nuts when he saw other dogs. All of those behaviors were gone within 3 months and replaced with really nice manners. Part of that was getting him adequate exercise (1.5 to 2 hours/day), incorporating training into every aspect of his daily routine and redirecting him to acceptable behaviors (like grabbing a toy when he got excited). I set limits for him and was fair and consistent and we had (and still have) lots of fun.