I haven't heard of vets doing this with human food since we went overtly processed. When I was growing up, my brother had a cat and I remember that we fed him baloney to and he did fine. This was in the 1960's when meat and cold cuts weren't as processed as they are today.
Because the meats are more processed, I would stick to grass fed and organic. Otherwise you could be giving her something that is shot up with Anti-biotics that can cause more problems. Going as clean in this as possible may work. Then there is canned tunafish made for cats, the way they can eat it. Trader Joe's carries it. You also be able to get it at PetSmart.
When my cat who passed, was living and he had digestive and weight gain problems, the Vet put him on Science diet. That worked for him. Each case is different too.
