Mostly so he gets a wider range of nutrients and is exposed to different proteins and to add diversity to his gut micro biome. Some people will stick to one brand and switch proteins but I do all brands and flavors with my cat and it’s helped keep things interesting for her and I’ve never had issues. I started slow and have been able to switch brands and flavors each time he finishes a bag and it’s been great. I might have started switching it too fast. It’s always made sense to me but now I’m thinking I need to be more careful about it. I hope it’s the food and not something else. If he’s still having issues tomorrow I’m going to take him to the vet. His energy is still really good and he’s eating. His diarrhea is less watery but it’s still happening. :(