What Is the Renal Diet? Foods to Eat and Avoid When You Have Kidney Failure

If you have chronic kidney disease, your provider has likely mentioned a “renal diet” to you. (“Renal” is a medical term that refers to anything related to the kidneys.) When you have abnormal kidney function, there are some special diet and nutrition guidelines that can help keep you healthy. This is not just about choosing foods that are good for your kidneys. It also means avoiding ingredients that can easily build up in the blood. The good news is that a renal diet still includes plenty of flavorful foods, so you can satisfy your stomach while going easy on your kidneys. 

Why is a renal diet important?

Your kidneys filter waste from the blood and balance the fluids and electrolytes in the body. Your diet is the source of a lot of your fluids, electrolytes, and waste. So if you have abnormal kidney function, food choices are important. A renal diet is important for two main reasons:

1. Certain foods can interfere with the kidney’s ability to filter waste from the body and balance fluid. For example, a diet that is high animal protein can accelerate kidney damage.

2. Foods can contain substances that are harder for the kidneys to process when they are not functioning at 100%. For example, foods that are high in sodium and potassium can lead to a toxic buildup in the body.

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What foods should I avoid if I am on a renal diet? 

The renal diet may look a little different from person to person. It depends on your stage of kidney disease and whether you have any other medical conditions. So it is important to work with your provider — and possibly a nutritionist — to find the best personalized plan for you. 

In general, people with kidney disease should limit foods that are high in the following substances.

Sodium (salt)

High amounts of salt can accelerate kidney failure by:

• Damaging blood vessels 

• Causing a buildup of protein in the urine

Processed and prepared foods tend to have higher levels of salt. When buying food at the store, it is always important to look at the salt content on the nutrition label. And it is helpful to know that most fast foods and restaurant meals contain a lot of salt.

Potassium

Potassium is one of the more dangerous electrolytes that can build up in the blood when you have kidney disease. The medical term for this is hyperkalemia. Too much potassium can lead to serious problems with how the heart beats. Foods that are high in potassium include: 

• Bananas

• Avocados

• Oranges

• Melons

• Potatoes

• Tomatoes

• Spinach

• Beans

Phosphorus

This is another electrolyte that can build up in the blood when you have kidney disease. High levels of phosphorus can cause calcium to leave your bones, making them weak. This also leads to excess calcium in the blood, which can get stuck in the heart or blood vessels and increase the chances of heart attack or stroke. Foods that are high in phosphorus include:

• Bran cereals and oatmeals

• Dark-colored drinks, like colas, beer, and iced tea

• Milk and dairy products

• Chocolate

• Meat, like beef, chicken, and certain fish

Saturated Fat 

Fats help the body absorb vitamins, and every person needs some fat in their diet. But if you have kidney disease, you’ll want to avoid saturated and trans fats. They can build up in the blood, heart, and kidneys. Foods that contain these fats include:

• Butter

• Lard

• Egg yolks 

• Red meat 

• Sweets like cookies and cakes 

Protein

When you eat protein, your body breaks it down and the kidneys then remove the resulting waste products through the urine. People with kidney disease should limit certain types of protein to avoid too much waste buildup. They should especially avoid processed meats like bacon, sausage, and deli meats. 

People on dialysis may receive more specific guidelines for healthy proteins to include in their diet. This is because dialysis removes protein from the blood, which we discuss more below.

What is the best diet for my kidneys?

The renal diet is not all about restriction. There are plenty of foods that you can incorporate into your meals that can help protect your kidneys and keep them running smoothly. Below are some of the best foods for kidney health.

• Strawberries and blueberries are good fruit options because these healthyberries are low in sodium, potassium, and phosphorus.

• Red grapes have been shown to decrease inflammation and can help protect your kidneys.

• Red peppers are low in potassium but packed with other nutrients. 

• Cauliflower is high in antioxidants like vitamin C, folate, and fiber. 

• Cabbage contains what are known as phytochemicals, which reduce inflammation in the body.

• Buckwheat and bulgur are lower in sodium, potassium, and phosphorus than other grains, such as oats and quinoa.

• Olive oil is packed with anti-inflammatory compounds to keep your kidneys healthy.

• Garlic has anti-inflammatory and antioxidant properties, making it a great option for people who are looking to add flavor to their food while protecting their kidneys.

• Egg whites are a good source of healthy protein but are not high in fat or potassium, making them a preferred choice for people with kidney disease.

• Lean meats are better than fatty meats. And they tend to have lower amounts of potassium, sodium, and phosphorus than other proteins. But keep in mind that any animal protein should be eaten in moderation.

If you are looking for diet plans that incorporate these foods, you might check out:

• DASH: The Dietary Approach to Stop Hypertension diet is recommended by the National Kidney Foundation. 

• The Mediterranean diet: This diet is high in plants, fiber, and grains.

But neither of these diets is recommended for people who are on dialysis, since they have specific nutritional needs that these diets may not meet. If you are on dialysis, don’t feel discouraged. Talk to your provider about the best diet for you to help keep your kidneys happy.

Can the right diet help prevent kidney problems?

Yes. Research shows that a healthy diet can decrease the risk of kidney damage and disease. Most of this research defines a healthy diet as one that follows many of the guidelines above. That is, a diet that is rich in fruits, vegetables, and healthy proteins. No matter what your baseline kidney function is, the renal diet provides helpful guidelines to keep your kidneys as healthy as possible. 

Why trust our experts?

Written by:

Cherilyn Davis, MD

Cherilyn Davis, MD, is a board-certified pediatrician in New York City. She has held local and national roles at the American Medical Women’s Association including board member of the physician division and physician chair of social media.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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