Yeah you want food high in protein. Most vets immediately want to push the "prescription only" diets which is low protein so they'll keep losing weight. It's also not that palatable to most cats, the carbs can be high because they use that in place of more protein and it can be even most expensive than other foods.
It all depends on your cat though.
Is Louis overweight, or losing a lot of weight?
What are his lab numbers for BUN/creatinine, phosphorus, calcium, sodium? Those are the BIG ones to watch.
If he needs to maintain or gain weight, look for foods (DRY MATTER) that is 40-50% protein but watch the fat content. If his liver numbers are up, keep the fat content lower.
Phosphorus UNDER .8 (dry matter), ideally .5 or lower if you can find it.
Sodium UNDER .5 (dry matter), ideally .3 if you can find it.
You want 2x the calcium to the phosphorus in lab results. For example if phosphorus is 4.1 then you want calcium to be at least 8.2.
Phosphorus binds to calcium and is then peed out or with bowel movements.
If his blood phosphorus is high, he needs more calcium so ask your vet about a phosphorus binder while you're transitioning him to a new food. Only use calcium based binders if Louis's calcium is lower than his phosphoros. Otherwise too much calcium will create new problems.
Hydration is pretty much ESSENTIAL with CKD cats, even Stage 1. Always have out a bowl of fresh water, only feed wet food if you can, and also try and transition your cat into eating the wet food with water added/mixed right into it. It might take awhile and some cats don't go for it, but it's worth a try. There's also subQ fluids which are great. Those can be given anywhere from 2 - 4 times a week, depending on blood work and the overall health/state of your cat.
All the water Louis gets from his bowl, his food, subQ, etc. ALL goes into helping flush out the high BUN/creatinine numbers. The water acts like a bolster for the kidneys.
B vitamins, especially B12, omega 3 fatty acid are all good to supplement. Watch his potassium level too, with all the water it might get low and he might need a supplement.
Watch out for high blood pressure too. If it's high, get medicine for it.
I agree about Tanya's site, the website itself is AMAZING but can be overwhelming. I'd use this link first -
http://felinecrf.org/just_diagnosed.htm They also have a forum you can join.
Good luck to you and your Louis!
EDITED TO SAY - a lot of CKD cats will get upset stomachs and vomit so always try have something on hand to help that, like REGULAR Pepcid, 10mg per pill. NOT "Pepcid Complete", etc. Just plain, regular, Pepcid 10mg. You can split each pill into 1/4 and give every 12 hours. You can pill it or you can crush it and mix it with food. If you're mixing meds or supplements with food, try to ONLY use the amount of food you need to cover the "taste" of the medicine. You want your cat to eat it all in 1 go, if you can.
If the nausea/vomiting gets worse, ask for Cerenia from your vet. The upset stomach is usually due to high BUN/creatinine levels.
