Originally Posted by pattymac
The vet didn't think he'd need it because of the higher protein being hard on his kidneys
That would be a myth, although in the case of low quality plant
protein, that might be somewhat plausible. But feeding good quality (ie easily digestible and assimilable) meat protein to a carnivore does NOT damage their kidneys and I'm not sure why vets get so hung up on this. Here's a good explanation from Dog Food Advisor which is also applicable to cats:
Does High Protein Cause Kidney Disease?
The Veterinary and Aquatic Services Department of Drs. Foster and Smith addresses what it refers to as a false rumor regarding high protein diets:
“High protein pet foods are NOT harmful to a normal animal’s kidneys. As an animal’s body digests and metabolizes protein, nitrogen is released as a by-product.
“The excess nitrogen is excreted by the kidneys. A high protein diet produces more nitrogen by-products and the kidneys simply excrete the nitrogen in the urine.
“While you may think this would ‘overwork’ the kidneys and lead to possible kidney damage, this is not true. The kidney’s filtering capabilities are so great that even one kidney is sufficient to sustain a normal life.”
Better Quality Protein
Fewer Nitrogen By-Products
So, then, why do so many veterinarians still believe a high protein diet is dangerous to older dogs and kidney health?
“The myth that high protein diets are harmful to kidneys probably started because, in the past, patients with kidney disease were commonly placed on low protein (and thus low nitrogen) diets.
“Now, we often put them on a diet that is not necessarily very low in protein, but contains protein that is more digestible so there are fewer nitrogen by-products.”