One of my pups, Cookie, has lymphangectasia, a protein losing enteropathy and also IBD; and I consulted with a vet nutritionist and I am home cooking for her. She is doing fantastic....that condition is managed with proper diet. I have exact amounts that I cook for her each day...everything is drawn out for me including the supplements. I don't make this up on my own. It is not hard to do and, as I said, it has saved her life. She was very, very sick in December and is thriving now.
A couple of years ago I had consulted with a vet nutritionist for another pup who has since passed. He had pancreatitis and also renal issues so all of the dog foods were a problem for him. The home cooked diet I was given was great for him and kept him alive for much longer than he would have been without it.
I encourage you to go to
American College of Veterinary Nutrition and really consider a vet nutrionist consult.