@kzeiss I am currently on the edge of Stage 4 and Stage 5 in my journey. Here is a link to some recipes from Mayo Clinic for renal diets: https://www.mayoclinic.org/healthy-lifestyle/recipes/kidney-renal-diet-recipes/rcs-20522796

In general, as @stephanierp mentioned, our diets change up as we progress through kidney disease. The goal is to not stress our kidneys any more than necessary, to try to preserve function as long as we can. Having PKD means your son has probably been dealing with his kidney issues for a while, right? Careful, useful protein, like found in shakes, can help, eating healthy is always good! If he has access to a renal dietician, take advantage of that, who will help him look at his labwork and determine what will be best for him individually.

Here is a link to the Mayo Clinic information about PKD, which you might find interesting to read. https://www.mayoclinic.org/healthy-lifestyle/recipes/kidney-renal-diet-recipes/rcs-20522796
And here is a link to National Institute for Health information on PKD and diet: https://www.niddk.nih.gov/health-information/kidney-disease/polycystic-kidney-disease/eating-diet-nutrition

Where will your son be listed for transplant, if you care to share?
Ginger