Spinach is GREAT for your dog. It has tons of nutrients he might not get otherwise.
I wanted to make a comment about garlic. I understand that it is toxic in large quantities but it is used holistically to prevent fleas and as an antioxidant. As with many things, a small amount is good, a large amount is a problem.
We've started Bogie on the things my Springer LOVED. In fact, my Springer turned his nose up on any dog treats! He just wanted.....
-zucchini slices ( I had bags of these sliced and ready to go)
-asparagus (When we had asparagus, I'd cut off the ends and saved for him.........)
Last night the trainer said BANANA'S
I think the "no human food" thing is to avoid junk and additives like salt and sugar. All stuff that humans don't need anyway!
I add grated carrots, spinach and zuccini to Rosie's food. Every couple of days I will also use a little less dry food and and in some egg, cheese or yogurt. She loves those days and looks at me after her meal with that "Yum! Is there anymore, Mom" face.
Denver has always been fed "human food " along with his
He gets chicken/rice/oatmeal/green beans mixed with Lean cuts canned dog food. He is never fed from the table and he goes to his "spot"
when we are eating.