Thanks, Jessika. I'll ask my vet.

Oscar's weight and arthritis were managed well by diet and fish oil. Cole was always a bit heavier, and the most rigid monitoring seemed to do little. My vet thought that the pain he was in was a major factor in him not moving more, though he will ask me to come play with him!

He has been so much calmer, not over-grooming. We'll stay with the Metcam and hypo food for a while. What I want to ask my vet is if the food you mention can be tolerated by a cat who is food-allergic. Cole threw up another hairball over a week ago and gagged up two mornings in a row. My vet said that can indicate food allergy, even if there ARE hairballs. I was dosing Cole with the Petmalt from the vet! Since he's on the hypo food - no problems whatsoever.

So we'll see.