I think IBD has many different causes, that is why the same thing doesn't work for every kitty. My kitty was only 18 months old when he had his first flare. He also didn't start with mild symptoms, he was hospitalized on an IV with his first flare. I still don't think diet had anything to do with his flares. There was simply no rhyme or reason to the flares. He would be fine when I left in the morning and I would come home to the stains on the floor where he had been vomiting bile. He would go anywhere from a few weeks to a few months between flares. The only dietary thing I found that he couldn't tolerate was beef. That was because his reaction was very obvious and very quick.