Understanding the Renal Diet: Protein

The most common question that dietitians hear from patients diagnosed with CKD is, “What should I eat?”  It can seem confusing when you hear or read different things. Renal (kidney) diets minimize the amount of waste in the blood and decrease the amount of work the kidneys do. Protein, sodium, potassium and phosphorus are the main considerations of a renal diet. The next few blog entries will discuss the general dietary guidelines for CKD to hopefully answer that question.

Kidneys are your body’s filters. When you have chronic kidney disease (CKD), any stage of CKD, you lose the ability to get rid of nitrogenous protein waste from foods you eat or drink, and it starts to build up in your blood. This is called uremia. Symptoms of uremia include nausea, bad taste in the mouth, loss of appetite, and weakness. If you have CKD stages 1 or 2 (GFR of 60 or higher), eating less protein can slow down the progression of kidney disease. Protein comes from both animal sources – like beef, pork, poultry, eggs, fish, shellfish, and dairy – and plant sources, including beans, legumes, and tofu. Protein powder supplements are usually made from whey or soy and are not recommended on a low-protein diet. If your tests show you have protein in your urine (proteinuria) or high blood urea levels (azotemia), or both, eating less protein becomes very important. Too much protein can irreversibly damage your kidneys. Protein requirements are determined by your stage of kidney disease, your weight, your urine protein results, whether or not you have diabetes, and your nutritional status.

In general, for CKD stages 1 and 2, the current recommendation is to limit dietary protein to no more than 0.8 grams per kilogram of your ideal body weight.  For example: if your ideal weight is 150 lbs or 68 kg, your protein needs are: 68 kg x 0.8 g/kg = 54 grams of protein or less per day. Once your glomerular filtration rate (GFR) starts to decline, it is better to get more plant-based proteins, as they break down to less urea than animal proteins.  A renal dietitian can help you find the right amount and type of protein for you.

If you have CKD stages 3-5 (GFR 59 or lower), unfortunately, you will need to restrict your protein even more. Studies now show that limiting protein to 0.55-0.60 grams per kilogram of your body weight can delay decline in kidney function.  For example, if your weight is 150 lbs or 68 kg, your protein needs are: 68 x 0.6 – 0.8 g/kg = 40-54 grams per day. This equals about 4-6 ounces of protein from animal or plant sources per day. If you are diabetic, 0.8-0.9 grams per kilogram of your ideal body weight is reasonable. Sometimes a doctor may prescribe keto acid analogues to meet protein requirements of very low-protein diets to prevent malnutrition. Protein exists in limited amounts in starchy foods and grains, so that needs to be accounted for as well. It may sound difficult and maybe unrealistic. However, a renal dietitian can help you plan out a diet that will work for your preferences and your lifestyle.  

Even though you are eating less protein, you still need to eat enough calories from other food groups to prevent weight loss and muscle wasting.There are other dietary factors to be familiar with in addition to limiting protein, depending on if you also have diabetes, high blood pressure or hyperlipidemia.

This information is meant to be used as a resource and is not meant to replace medical advice. For more information, contact programs@kidneyhi.org