High-protein diets are everywhere right now, and the appeal makes sense. Protein helps build muscle and can support weight loss. As a nephrologist, though, I want patients to understand that more protein is not automatically better, especially for anyone with existing kidney disease.
Every time you eat protein, your kidneys have to work to filter the waste products it creates. In a healthy kidney, this is not a problem. In a kidney that is already under strain from diabetes, high blood pressure, or an autoimmune condition, extra protein means extra pressure on the delicate filtering membrane inside each nephron, called the glomerular basement membrane. Over time, that added pressure contributes to the same thickening and scarring process that drives chronic kidney disease forward.
For patients with kidney disease, the general recommendation is 0.8 grams of protein per kilogram of body weight per day. To put that into practice, take your weight in kilograms and multiply by 0.8. That is a reasonable daily protein target, not an amount to exceed.
This does not mean protein is dangerous for everyone. Healthy kidneys can typically handle higher protein intake without issue. If you have been diagnosed with chronic kidney disease, or you have risk factors such as diabetes or high blood pressure, a high-protein or ketogenic diet deserves a conversation with your doctor first.
Diet matters well beyond protein. I tell my patients to think of food as fuel first, not only as pleasure. Fresh vegetables and fruit, baked or broiled lean proteins such as fish, chicken, and turkey, and, most importantly, plenty of plain water support kidney health. Processed foods, canned foods, and high-sodium items such as bacon and sausage work against it. A simple test I share with patients: if a food can go bad, that is usually to avoid can or processed type of food.
Water deserves special mention. Your kidneys function like a filter, and filters need water to work. Most adults should aim for roughly two liters of water a day, adjusted for body size and your doctor’s guidance, with plain water as the primary source rather than juice, soda, or energy drinks.
If you are considering a high-protein diet and you have any risk factors for kidney disease, talk with your doctor before making the change.
Dr. Mitchell Hernandez is an Internal Medicine board-certified and nephrologist with Nephrology Associates in Panama City, Florida, and a member of the Emerald Coast Medical Association. Hear more from Dr. Mitchell Hernandez on Episode 23 of Emerald Coast Medical Mastery.
