Hi Losul,
The physiology behind it is the same reasoning as with people; urea is a solute. From Nutrient Requirements of Dogs and Cats ” For example, higher protein and/or mineral content of food may increase the solute load and subsequent degree of water consumption and urine production” From Applied Veterinary Clinical Nutrition in regards to patients with renal compromise: “Modified protein diets can help diminish the degree of polyuria and polydipsia because less solute is delivered to the kidneys in the form of proteinaceous wastes.”
There could be other factors as well. I’d think it reasonable that with a raw meat based diet you would have less water loss via feces than a commercial kibble diet.
Yes absolutely, low protein diets ( much lower than AAFCO) will cause dilute urine. The reason again is solute load. In this case is it so low that the concentration gradient in the kidney isn’t maintained.
