Renal or chronic kidney disease is a progressive and gradual decline in kidney function.
With chronic kidney disease, your kidneys can’t effectively filter blood to remove waste and extra fluid and perform other functions to keep you healthy.
Fortunately, with the right diet, you can minimize kidney damage and slow kidney disease progression.
This article provides a list of foods to eat and limit on a renal diet and includes a sample renal diet menu.
What is kidney disease?
Chronic kidney disease is a chronic condition where the function and health of your kidneys progressively decline over time.
Doctors assess your kidney function using a measure called the glomerular filtration rate (GFR), which measures how well your kidneys are filtering blood.
A normal GFR is 90 milliliters per minute (mL/min) or higher.
Based on GFR, there are five stages of kidney disease (1):
- Stage 1: Kidney damage with normal or increased GFR (>90 mL/min).
- Stage 2: Mild reduction in GFR (60-89 mL/min)
- Stage 3a: Mild to moderate reduction in GFR (45-59 mL/min).
- Stage 3b: Moderate to severe reduction in GFR (30-44 mL/min).
- Stage 4: Severe reduction in GFR (15-29 mL/min).
- Stage 5: Kidney failure (GFR < 15 mL/min), eventually requiring dialysis or a kidney transplant.
Stages 3–5 are classified as advanced chronic kidney disease.
Unlike acute kidney injury, where the kidneys can completely recover, you can’t reverse kidney damage once it has occurred.
However, you can prevent further progression with diet.
Renal diet restrictions
Chronic kidney disease prevents your kidneys from efficiently regulating your sodium, potassium, and phosphorus levels.
The condition also prevents your kidneys from filtering and urea from your blood.
Urea is a waste product that forms when you metabolize protein.
As such, a renal diet typically focuses on limiting your intake of sodium, potassium, phosphorus, and protein.
However, your level of restriction will depend on your stage of kidney disease, current health status, and other factors.
Sodium helps maintain normal fluid balance and supports nerve and muscle function.
With advanced chronic kidney, guidelines recommend limiting sodium to 2.3 grams (2,300 mg) per day — the same recommendation for healthy people — to reduce blood pressure and reduce fluid buildup (2).
Limiting sodium to this amount may still be beneficial if you have less advanced chronic kidney disease (stage 1–2) to prevent further progression.
Sodium is abundant in processed foods like snack items, processed meats, fast food, soups, and pizza.
Conversely, fruits, vegetables, whole grains, and lean meats are naturally low in sodium.
Choose foods that contain 140 mg of sodium or less per serving on the nutrition facts panel.
Potassium plays an important role in proper kidney and heart function, muscle contraction, and nerve function.
Diets rich in potassium are associated with health benefits like lower blood pressure, but in people with advanced chronic kidney disease, potassium can increase to harmful levels, causing irregular heart contractions.
A renal diet typically restricts potassium to 2 grams (2,000 mg) per day.
Food manufacturers list the amount of potassium their products contain on the nutrition label.
High potassium foods contain more than 200 mg of potassium per serving, whereas low potassium foods contain less than 200 mg per serving.
Keep in mind that a low-potassium food can become a high-potassium food if you eat a large amount and vice versa.
Phosphorus is a mineral necessary for energy production, bone health, and acid-base balance, but too much can be harmful.
Chronic kidney disease is the most common cause of high phosphorus or phosphate levels, which can weaken your bones and cause the harmful buildup of calcium in your blood vessels, lungs, eyes, and heart.
A renal diet generally restricts phosphorus to 800-1,000 mg per day.
Many foods naturally contain phosphorus, but the phosphorus isn’t well absorbed.
In contrast, your body can absorb 80–100% of the phosphorus added to foods.
Most packaged rice and pasta meals, frozen meals, and other highly processed foods contain a phosphorus additive.
Food manufacturers are not required to list the amount of phosphorus their products contain, but you can identify products that contain a phosphorus additive by reading the ingredients.
Here are some commonly used phosphorus additives to limit:
- dicalcium phosphate
- disodium phosphate
- phosphoric acid
- monosodium phosphate
- todium hexameta-phosphate
- sodium tripolyphosphate
- tetrasodium pyrophosphate
- trisodium phosphate
Protein keeps your immune system strong, repairs and rebuilds your body’s tissues, and transports and stores nutrients, among other important functions.
However, consuming too much protein with advanced chronic kidney disease can put excess strain on damaged kidneys that healthy kidneys would be able to handle.
If you have advanced chronic kidney disease, guidelines recommend following a low-protein diet providing 0.25–0.27 grams per pound (0.55–0.60 grams per kg) of body weight (2).
If you have diabetes, these guidelines recommend a higher intake of 0.27–0.36 grams per pound (0.6–0.8 grams per kg) of body weight.
For a 150-pound (68-kg) person these guidelines translate to 38–41 grams of protein per day if you don’t have diabetes and 38–54 grams if you have diabetes.
However, because these guidelines call for a protein intake at or below the recommended dietary allowance (RDA) of 0.36 grams per pound (0.8 grams per kg), you should receive close supervision from your doctor and registered dietitian.
If you receive dialysis, an protein intake above the RDA of 0.45–0.55 grams per pound (1.0–1.2 grams per kilogram) of body weight is recommended to maintain nutritional status and replace the protein removed during dialysis.
Plant-based foods like fruits, vegetables, and whole grains contain some protein but are much lower than animal-based sources.
With a low protein diet, it’s especially important to eat enough calories to prevent protein from being used as energy.
Your calorie needs will vary depending on your age, gender, physical activity level, chronic kidney disease stage, and other diseases present.
Sample renal diet menu plan
Here’s a one-day sample renal diet menu plan:
Breakfast: 1 scrambled egg, oatmeal with blueberries, and black coffee
Snack: hummus with vegetables like celery, carrots, and bell pepper slices for dipping
Lunch: avocado and tuna salad wrap with strawberries
Snack: air-popped popcorn and pear
Dinner: 3 ounces of chicken (85 grams) with white rice and asparagus
Snack: apple slices with peanut butter
Remember that your doctor and registered dietitian will determine which nutrients you need to restrict and the level of restriction.
The bottom line
Your diet plays an important role in preventing the progression of renal or chronic kidney disease.
A renal diet generally restricts your intake of sodium, potassium, phosphorus, and protein.
Your doctor and registered dietitian will determine which nutrients you should restrict and the level of restriction based on your stage of chronic kidney disease and other factors.