Which is better for a cat with Kidney Disease (CKD) to eat, a high protein diet or a low protein diet?

Not all vets push that low protein diet. My vet 'prescribes' a high quality canned food with a quality protein source - meaning NO by-products. By-products are hard on the kidneys. Low protein diets are not appealing to cats, and they lead to muscle wasting. I've maintained elderly cats on canned high protein diets (Wellness being a favorite) and they died of non-kidney issues. I also have a cat with uremic dysplasia (a birth defect where the kidneys are too small) diagnosed at age 18 months. Bad kidney numbers - same diet. He's now 13 and doing well. I'd rather feed a quality diet than one with by-products, fillers and chemical preservatives even if it is a special "kidney diet".

Why do holistic foods have all those things? Because it makes people want to buy them. And they are so far down on the ingredient list for most of them that it doesn't matter. When a cat eats a mouse or a bird, it does consume the grains and seeds or berries in there stomach, in those very small amounts. If it's a dry food, it needs some sort of carbohydrate binder to keep the kibbles together - you can't have an all-meat kibble, you need some sort of starch. The better foods have these items as that binder, rather than corn or rice.