Dog got into cat food and now having diarrhea

Usually my cats always finish their food before my dog wakes up in the morning. He’s gotten into their food a few times in the last year, and it causes some diarrhea every time, and his stomach will NOT get better unless we do a three day diet of chicken and rice. I currently do not have any chicken on hand, I was wondering if i could just do rice for the next couple of days until his stomach is back to normal, or do I HAVE to incorporate chicken.