My cat, who is 18 years old, has recently developed quite the sensitive stomach. He has an upset tummy nearly every day, & I think it’s probably his food. I’m trying to find one that fits all 3 qualifications, but I can’t seem to find a cat food for senior and sensitive stomach. He’s been eating Iams indoor senior formula, and I’m considering switching him to Nutro Senior, because it says it’s easy to digest. Has anyone else used Nutro, or have any suggestions for a good brand of senior sensitive stomach food?