In Dr. Sear's first book, "Enter the Zone" on page 74, he has a chart that compares four different diets in terms of total daily grams of each of the three macronutrients consumed per day. In this chart, "Figure 7-5", it shows that the amount of protein and fat consumed in grams per day in a Zone-favorable diet is equivalent to the amount recommended in the ADA diet, Recommended "Healthy" diet, and Vegetarian diet.
I believe that excess protein can be difficult on the kidneys. I, admittedly, don't know how many grams of protein are allowed per day on a renal-diet. You could perhaps compare what your dr.'s/dieticians are recommending to you in terms of protein grams per day and then figure the grams of protein per day you would be alloted in the Zone. (i.e. if you are calculated to be 12 blocks per day, that would be 12 x 7 grams of protein per block = 84 grams/day) If this recommendation meshes with your dr.'s and dietician's advice re: protein, I'd think it ? might be o.k.
Also, since the Zone gives you even doses of protein (in small amounts throughout the day) rather than perhaps consuming all of your protein at dinner-time, for example...I'd think this might be gentler on the kidneys in this respect. ????
Be sure to check with your dr.'s and dietician(s) on this to be sure, K?
? hope this helps.