OK, this is making me crazy.
I'm getting questions from both veterinarians and pet owners based on bad information from the 'holistic' websites. Essentially, the rumor is that low protein diets used for kidney disease lead to muscle atrophy long term.
These diets (examples are Hill's K/D, Royal Canin LP, and Purina NF)contain protein levels that are more than adequate for maintenance and can even sustain growth. (Not that you would want to try that on your puppy or kitten). That's PLENTY of protein to maintain muscle mass when all else is normal, like calorie intake and exercise.
The reason chronic renal patients lose weight and muscle long term is that *they are not eating enough*. They are starving. When they don't get adequate food, they don't get adequate calories or protein. Starvation leads to fat and muscle loss.
If your kidney patient is losing muscle mass, the thing to do is find out why he or she isn't eating well enough, and correct that problem.
Really - the low protein diets are not the problem!
Not that some would believe a veterinarian trained in nutrition above a random self taught expert on the internet, but that's another issue. Rant over. Thanks for listening.