Renal Diet: A Complete Guide to Eating for Kidney Health

What Is a Renal Diet?

A renal diet, or kidney health diet, is an eating plan meant to support kidney health and help slow the progression of kidney disease. Due to the complexity of kidney function, a kidney disease diet plan is not a cookie cutter diet, but one that’s personalized based on current kidney function, lab values, and individual health status. 

The purpose of renal nutrition is to help the kidneys manage what they can no longer filter out of the system efficiently. Kidney disease stages and diet are deeply intertwined, meaning that foods to avoid with kidney disease will vary depending on the stage of CKD (chronic kidney disease) someone is in and whether or not they are on dialysis. Working with a renal dietitian, or a dietitian who specializes in chronic kidney disease nutrition, helps to ensure a renal diet is tailored to individual medical conditions. 

Why Diet Matters When You Have Kidney Disease

In healthy kidneys, waste products created by normal metabolism as well as extra water are removed from the blood before leaving during urination. Kidneys also keep the body's nerves, muscles, and heart in good working order by maintaining the right levels of sodium, potassium, and calcium.

Blood pressure and hydration are maintained by the kidneys by controlling how much fluid stays in the body. When kidney function is on the decline, one can experience swelling, fatigue, and other symptoms as waste builds up in the blood when it’s not able to be excreted properly. Extra vitamins and minerals like potassium and sodium can also build up when the kidneys are not working, and this can be dangerous to health if not managed. 

By providing relief on the workload the kidneys receive and balancing nutrients, knowing which kidney-friendly foods fit into a renal diet can help slow the progression of kidney disease and prevent further complications like osteoporosis, high blood pressure, and other heart problems. Chronic kidney disease can seem overwhelming and out of your control, but understanding chronic kidney disease nutrition is one of the most powerful ways to regain a feeling of control. 

The Main Nutrients to Manage on a Renal Diet

Sodium: Reducing Salt to Protect Your Kidneys

Sodium makes the body retain water. This increases the body’s total amount of fluid circulating, which can lead to high blood pressure if the kidneys cannot clear excess sodium properly. This can lead to further damage to the kidney’s cells due to the strain of the excess fluid. It also causes swelling, usually in the extremities. 

Typically, CKD patients who need to be on a low sodium diet are allowed 2,000mg of sodium or less per day. Some common, high-sodium foods to avoid include processed foods, added salt, canned soups, deli meat, fast food, salty sauces like soy sauce and hot sauce along with most restaurant food. Some simple tips to reduce sodium in the diet are to cook at home with whole foods, use herbs and spices instead of adding salt to meals, and look for low-sodium versions of dressings, sauces, and canned foods. 

When in doubt, read the Daily Value percentage on your nutrition facts label. The FDA notes that less than 5% per serving is low sodium and 20% or more is considered a high sodium food. 

Potassium: Finding the Right Balance

Potassium is a sensitive mineral that must be cleared by the kidneys to avoid a condition called hyperkalemia, which means dangerously high levels of potassium in the blood. Symptoms of hyperkalemia include muscle weakness, cramping, irregular heartbeat, and even sudden heart attack in extreme cases. 

Potassium recommendations vary depending on the kidney disease stages and diet followed by the individual as well as their lab values. Some common high-potassium foods to avoid include bananas, avocados, potatoes, tomatoes, dairy, and legumes. Don’t worry though, there are plenty of other fruits and veggies allowed on the renal diet. 

Some low potassium foods that can be alternatives include apples, berries, zucchini, cucumbers, and cauliflower. If you want to leach even more potassium from your food during cooking, cut veggies as small as the recipes will allow, soak in water for 2 hours before cooking, and boil to cook them until tender. Make sure you drain the potassium-rich water.

Phosphorus: Protecting Your Bones

Phosphorus is a mineral that helps build and maintain strong bones, but healthy kidneys are needed to keep phosphorus levels in balance. In chronic kidney disease, the kidneys may not remove excess phosphorus effectively, causing phosphorus to build up in the blood and triggering hormonal changes that pull calcium from bones. Over time, this can weaken bones and increase the risk of fractures, a condition often referred to as chronic kidney disease–mineral and bone disorder (CKD-MBD).

Phosphorus is a mineral that helps build bones and keep them strong, but the kidneys are responsible for balancing phosphorus levels in the blood. However, if there’s too much phosphorus in the blood, it can leach calcium from the bones and actually make them weaker. High levels of phosphorus can also cause strain on the heart and inflame blood vessels, which can lead to heart problems. 

Some high-phosphorus foods to avoid with kidney disease include dairy, legumes, nuts, whole grains and brown colas. You also want to read your labels for any phosphate additives in certain processed foods. Certain foods like frozen meals, deli meat, and bakery products like pancake mix and frozen waffles may have phosphates in them as they are often used as a preservative. Any ingredient with "phos" in the name indicates added phosphates, with some common additives including potassium phosphate and sodium phosphate. Your doctor may also recommend a phosphate binder medication which, when taken with phosphate-containing foods, will bind to the phosphorus to be excreted by the gut, rather than the kidneys.  

Protein: Getting the Right Amount

When the body breaks down protein, it produces acidic waste products like urea and ammonia. Healthy kidneys can get rid of these no problem, but in those with kidney disease, if these products build up to dangerous levels. So, protein intake must be closely monitored. Depending on your stage of kidney disease or if dialysis is being done, a dietitian may make varying recommendations for daily protein needs. 

Since protein intake is typically lower than those with healthy kidney function, it’s important to focus on complete, high-quality, lean protein sources with all of the essential amino acids included. These protein sources include fish, poultry, eggs, tofu, and other soy products. Just be careful about protein sources like dairy, nuts, and some legumes as they could be too high in phosphorus, sodium, or potassium for some. 

Fluids: Managing What You Drink

In later stages of CKD, the kidneys become less and less efficient at clearing waste and excess fluid through urine. Some individuals at certain stages may hardly urinate at all. So, if the amount of fluid consumed is not managed, it can lead to fluid overload in the body. Excess fluid causes the volume of the blood to expand which puts extra strain on the heart and can lead to serious conditions like congestive heart failure as well as high blood pressure. It can also damage some of the delicate kidney cells even further. 

Some signs of fluid overload include swelling in the extremities, face, and stomach as well as rapid weight gain, headaches, shortness of breath, and fatigue. To manage fluid intake, take control of your thirst mechanism by avoiding salty foods and chewing gum to keep the mouth moist. Many people with CKD may also carry a container to keep track of how much they drink throughout the day to ensure they don’t go over their individual recommendation, which varies depending on the person and their stage of CKD. 

Foods to Enjoy on a Renal Diet

Kidney-Friendly Fruits and Vegetables

So, let’s talk some good news and discuss kidney-friendly foods to include in your renal diet. Some produce that is low in problematic minerals include leafy greens like kale and swiss chard, red grapes, cherries, red bell peppers, apples, pineapples, cauliflower, broccoli, cabbage, and berries, especially cranberries.

Due to dietary choices being limited with renal nutrition, it is important to have a variety of fruits and vegetables to get a wide range of antioxidants. Talk to your nephrologist and renal dietitian to know how to properly portion certain fruits and veggies, as certain foods could still be problematic if overconsumed. Canned foods can be okay, but be sure to choose low-sodium options, check your labels, and always drain liquids which often contain excess sodium and potassium. 

Healthy Proteins for Kidney Health

The National Kidney Foundation indicates a standard protein serving size on a renal diet as 2–3 ounces of animal protein like fish and skinless poultry, 2 egg white, or ½ cup of plant proteins per meal. Some dairy protein may be consumed, but tends to be high in phosphorus and thus not appropriate for those at certain stages of kidney disease. Remember, focusing on complete proteins is more important than the amount of protein you eat. 

Grains and Starches That Work

The USDA and dietitians typically recommend the general population consume mostly whole grains as they contain notably more fiber and micronutrients than refined grains like white bread, white rice, and regular pasta. However, these grains are sometimes preferable for more kidney-friendly recipes containing grains as whole grains are much higher in phosphorus and potassium. 

That said, there is some evidence that some whole grains can still be handled by those with kidney disease, but how much is allowed should be discussed by a dietitian. One half cup of grains or a single slice of bread per meal is the standard for a kidney disease diet plan.

Foods to Limit or Avoid With Kidney Disease

When eating with kidney disease, knowing which foods to limit is key to help better manage the progression of the disease and limit the risk of complications. High sodium foods like canned soups and veggies, frozen meals, fast food, salty snacks like pretzels, crackers, and chips, as well as processed meats like hot dogs. 

High-potassium foods to avoid are typically fruits and vegetables, many of which are high in the mineral. These include avocado, potatoes, spinach, tomatoes, bananas, nuts, and some beans. High-phosphorus foods to limit include nuts, seeds, some beans, whole grains, dark soda like cola, and dairy products like cheese, milk, and yogurt. 

Please note that doesn’t mean you have to avoid these foods forever, but have to be mindful about how much you are having and how often. These are guidelines that can vary widely depending on your individual lab values and CKD stage. 

How Your Renal Diet Changes With CKD Stages

Early Stage CKD (Stages 1-2)

For those in the early stages of chronic kidney disease, the amount of dietary changes are typically minor as there is still a sufficient level of kidney function to manage clearing excess minerals, fluid, and protein. Instead of following a CKD diet, just focus on eating healthy for the heart and blood pressure, which means plenty of fruits and vegetables, proteins low in saturated fats, whole grains, and healthy fats to help manage blood sugar. This can help slow the progression of kidney disease and emphasize prevention of further health problems. 

Moderate CKD (Stage 3)

At stage 3, you’re going to need to play close attention to certain minerals in particular, especially sodium, potassium, and phosphorus, along with protein intake to a lesser extent. 

Stage 3 guidelines vary, but can be more specific based on lab values and if there are any other chronic conditions present such as high blood pressure or diabetes, so getting regular bloodwork done is wise for those with CKD. There are typically little to no restrictions on fluid intake at stage 3. 

Advanced CKD (Stages 4-5)

At the later stages of CKD, more care must be taken to monitor problematic nutrients through a carefully constructed CKD diet including limiting potassium, phosphorus, sodium, fluids, and protein. Help from a renal dietitian and close monitoring is very important, along with regular bloodwork to individualize these recommendations for better odds of success. 

Dialysis Diet Considerations

One important thing to note is that dialysis changes the nutritional guidelines of those with renal disease. Dialysis is the mechanical method of clearing waste products from the blood, with the machine basically operating as your kidneys for you when kidneys no longer have the function to operate even with diet modifications. 

Luckily, dialysis gives those with CKD a bit more flexibility in what they can consume,  but some diet modifications must be made to replace what’s been lost in the dialysis process. For example, protein needs are actually higher to prevent muscle loss and water soluble vitamins like Vitamin C and B vitamins typically need to be replaced as well.

A dialysis diet typically continues to restrict sodium, potassium, phosphorus, and fluid, but dialysis centers typically have renal dietitians to give more specific advice. Hemodialysis isn’t performed as often as peritoneal dialysis, which means diet is typically more strict on those with hemodialysis. As peritoneal dialysis is performed every day to perform kidney functions, a renal diet is often much more flexible on this form of dialysis. 

Practical Tips for Following a Renal Diet

When following a renal diet, being diligent about reading nutrition labels to find the presence of problematic nutrients and the amounts in each serving so you know how to portion certain foods correctly. Engaging in meal planning, batch cooking certain foods, and freezing kidney-friendly recipes can help make following safe renal nutrition at home less overwhelming. 

When eating out, checking out the menu ahead of time to see what meals fit your specific diet guidelines and what substitutes can be made can help mitigate social awkwardness or anxiety around ordering. When at family gatherings, corporate events, or potlucks, preparing your own food or letting the host know ahead of time that you are following a renal diet can help you navigate these situations. 

Some people on a kidney disease diet plan find it helpful to keep a food diary, track patterns, and identify any problems. Eating home cooked foods without salt can be tough for some, especially with certain cuisines that use sodium liberally. However, finding low sodium or salt-free versions of seasonings along with fresh herbs and spices can make food much less boring. 

Working With a Registered Dietitian for Kidney Disease

A renal dietitian is a dietitian who specializes in providing nutrition counseling, a personalized kidney disease diet plan, and proper nutrient management. They are trained to review the blood work of those with kidney disease to keep levels in healthy range and provide nutritional guidance for those undergoing dialysis. It’s important to have consistent, ongoing support and monitoring from a renal dietitian for optimal success, especially in the later stages of CKD as needs often change. 

Many insurance plans cover medical nutrition therapy for kidney disease and Top Nutrition Coaching matches patients with a dietitian, typically one with a renal speciality, to get renal diet guidance covered by insurance. 

Common Renal Diet Challenges and Solutions

The diet limitations can feel overwhelming for individuals who are newly navigating kidney disease, especially since many foods have overlapping restrictions and can clash with other chronic conditions such as diabetes and heart disease. Kidney-friendly recipes also have to consider budget, but foods that fit in a renal diet aren’t necessarily more expensive. 

Making one change at a time can help the process seem more manageable. Due to the buildup of waste products in the blood, many CKD patients experience loss of taste and appetite which can make following a renal diet more challenging. So, finding variety in meals and ways to enjoy these meals even with restrictions is important for sustainability and quality of life. Have conversations with friends and family about your new diet to recruit more support rather than judgment. 

Get Personalized Support for Your Kidney Health

Every individual with CKD is different and diet needs will vary depending on medication, the stage of CKD, dialysis, lab values, and the presence of other health conditions. Recruiting a renal dietitian to your health care team can significantly increase the odds of following a renal diet successfully and confidently with evidence-based, personalized advice. 

Top Nutrition Coaching makes it easy to connect with registered dietitians with a specialization in kidney disease care. Most clients pay $0 out of pocket to get matched with a renal nutritionist online and CKD patients can enjoy the convenience of virtual counseling with eligible insurance plans.

Frequently Asked Questions

What is a renal diet and why is it important for kidney disease?

A renal (or kidney-friendly) diet is a specialized eating plan that limits specific minerals, fluids, and proteins.

What foods should I avoid on a renal diet?

A renal diet generally requires you to avoid or significantly limit foods high in sodium, potassium, and phosphorus

How much protein should I eat on a renal diet?

If you have CKD, limit protein if not on dialysis and increase protein if on dialysis. Consult a dietitian for your specific protein needs.

What are the best low-potassium foods for a renal diet?

For a renal diet, focus on foods low in potassium to help protect your kidneys, such as apples, berries, pineapple, grapes, cauliflower, bell peppers, white rice, pasta, and lean meats.

How much sodium should I limit on a renal diet?

For a renal diet, focus on foods low in potassium to help protect your kidneys, such as apples, berries, pineapple, grapes, cauliflower, bell peppers, white rice, pasta, and lean meats.

What is phosphorus and why do I need to limit it on a renal diet?

Phosphorus is an essential mineral that, along with calcium, builds strong bones and keeps cells functioning. You must limit it on a renal diet because damaged kidneys cannot filter excess phosphorus, leading to a dangerous buildup that weakens bones and causes calcification in the heart and blood vessels.

Can a renal diet slow the progression of chronic kidney disease?

Yes, a renal (kidney-friendly) diet can help slow the progression of chronic kidney disease (CKD).

Is a renal diet the same for all stages of chronic kidney disease?

No, a renal diet is not the same for all stages of chronic kidney disease (CKD).

How do I read food labels for a renal diet?

Reading food labels for a renal diet requires close monitoring of four key nutrients: sodium, potassium, phosphorus, and protein

Can I eat beans and legumes on a renal diet?

Yes, you can eat beans and legumes on a renal diet! They are excellent sources of plant-based protein and fiber.