Your Vet knows the answers.
I am not a Vet.
I am writing my insight on this and things change as I learn more new wrinkles.
Consult your vet.
Your Dog (or other pet) will appreciate it, even if they are scared by the vet.
Chronic Renal Disease is the loss of function in Kidneys. It will eventually be fatal, if nothing else intervenes. At least that is what I've been led to believe. After all, your dog won't get dialysis. Won't happen. No transplants. Sorry.
I will fight it as much as I can, my own Lettie deserves as much.
Some of the symptoms make her hate food. She'll turn her nose up to just about anything she's eaten because it does some things to her generally to make her feel like crap. She's showing symptoms like she's got a queasy or sick stomach, so she turns away from most things I offer her. Even things like Yogurt that she's begged for many times, will make her go so far as to show her teeth at me with a growl.
First, offer small samples. Think "Hors d'oeuvres". Finger food. Snacks. Get yourself a good kitchen scale. Mine measures down to the gram, and trust me, I use it both in Metric and Imperial pounds and ounces. If you offer too much, I'd say you're going to throw it out. Limit yourself to 1 ounce at a time or 28 grams.
Second, be creative. My personal opinion is that the gloves are off. If it has calories and she wants it, she's getting it. You can't feed a dog onions, so that rule doesn't change. What I mean is that the border between dog food and people food has gone. I personally tend to graze, eat smaller portions whenever I feel the need. My Lettie will follow me into the kitchen, and if she even looks slightly interested, she's getting a sample. If she likes, I'll make more for myself.
Third, Count Calories. I do this for myself, and now I'm counting for two. In the case of her dog food, she was getting 1 cup of Purina Lamb And Rice twice daily. That works out to be around 700 calories. 350 in the morning, 350 at night. If your dog is refusing food, but snacking, she may be getting enough in nibbles so that the energy levels are enough.
Fourth, be flexible. Lettie is showing that she is more nauseous in the morning. She was always a morning person, but now she just looks at food like it is her enemy. Think "morning sickness", although we know in her case that that is impossible. So I give her the morning pills then take her for her walk after giving water. Come home and offer morsels. Tortellini for example. She loves them right out of the freezer like an ice cube. Lunch time, she'll mooch more.
Fifth, Phosphorous, Bad. I was told that specifically, foods high in phosphorous are to be avoided. I was told to include Yogurt, Cottage Cheese, Tofu, Beef, Chicken, Rice. If there's a lot of phosphorous in the food, you're going to make it harder on your dog's weakened kidneys, so be careful. Certain cheeses are acceptable (Feta, Cream Cheese, Cottage Cheese) and others are questionable. Search online the specific information, and see if it is acceptable. I'll have to watch how much of that VT Extra Sharp Cheddar I give her from this point on!
Sixth, Water Early, Water Often. But don't water late. My Lettie showed her problems first by having accidents at night. I didn't even notice the "leaking" until it got to be rather pronounced. She started drinking more and more water, and then all the sudden the water bowl was empty in the morning. So give her what she needs until dinner, then make sure that there isn't a giant amount sitting in the bowl overnight. Oh, and close the lid to the toilet. They will drink there. The trick is to give just enough water so that the water bowl has a little bit in the morning. This takes practice. In our case right now it is between 26 and 32 ounces per day, with 20 ounces immediately after giving her pill in the bowl, and topping it off with 6 more later, whenever later is.
At this point, it's a long post. I'm going to cut off here. I may return with a later post as I find more things out. Like I said, it's a learning experience for me. What you need to remember is that the strategies in Dogs are the same for a Human with kidney problems. If the Kidney Foundation recommends it, it's probably going to work for your dog. We're really not that different after all.