Kidney Disease and Weight Loss

“Kidney Disease and Weight Loss” was written by Jen Hernandez RDN, CSR, LDN and edited/updated by Aly Bouzek, MS, RDN. Jen is a Registered Dietitian and Board-Certified in Renal Nutrition at Plant Powdered Kidneys

While many people spend time, money, and effort towards weight loss, some lose weight simply from a diagnosis of kidney disease

And while kidney disease and weight loss aren’t always thought of as being intertwined, weight loss can be a crucial factor to pay attention to when caring for your kidneys.

Chronic Kidney Disease 101

Chronic kidney disease (CKD) affects over 37 million people in the United States, and 1 in every 3 Americans are at risk for kidney disease.

Chronic Kidney Disease

Causes of Kidney Disease

There are many causes of CKD, which is why it has become so prevalent in the United States. And while some are very familiar, not all are known.

Diabetes

The top cause of CKD is diabetes. Diabetes affects over 11% of the US population as of 2022. Prediabetes affects even more – 96 million people (that’s 38% of the US population) have diagnosed prediabetes.

Whether it’s type 1, type 2, or even pre-diabetes, uncontrolled blood sugar can cause damage to the delicate kidney filtration system in your body.

For a diabetes diagnosis, a blood test of your glucose is usually the first step. A fasting blood sugar of over 126 mg/dL in two separate tests can confirm a diagnosis of diabetes.

Another type of blood test is the hemoglobin A1c (or A1c). An A1c of between 5.7 and 6.4% is classified as prediabetes. An A1c of 6.5% or greater is classified as a diabetes diagnosis.

Type 1 diabetes is also called “juvenile diabetes” as it is discovered in the early stages of childhood. This is due to the fact that the pancreas does not produce any insulin.

Type 2 diabetes, or “adult onset diabetes,” is typically diagnosed in adulthood. It is caused by a poor response to the insulin that is produced by the pancreas.

Hypertension

High blood pressure, otherwise known as hypertension, is the second top cause of kidney disease in the United States.

In 2017, the American Heart Association changed the blood pressure guidelines to become more strict in when to define a blood pressure as being excessive.

High blood pressure is defined as a reading of 130 mm Hg for systolic (the top number) and higher or 80 mm Hg and higher for diastolic (the bottom number). Both numbers do not need to be high to have high blood pressure.

Glomerulonephritis

This is the third highest cause of kidney disease in the United States. Glomerulonephritis is a condition in which the glomeruli, or kidney filters, are damaged. The damage can occur very quickly or over a longer period of time.

Autoimmune Diseases

Many people with autoimmune diseases can develop kidney disease. Some examples include:

  • Lupus
  • Goodpasture’s syndrome
  • Wegner’s disease
  • IgA Nephropathy (Berger’s disease)

Other Causes of Kidney Disease

Other causes of kidney disease include:

  • Polycystic kidney disease (a genetic disorder)
  • Infections
  • Nephrotoxic drugs
  • Heavy metal poisoning
  • Alport syndrome (a genetic condition)

Kidney Disease Risk Factors

Besides having one of the top causes of kidney disease, there are other factors that may increase your risk of getting kidney disease. Some of those factors are:

  • Smoking or history of smoking
  • Obesity
  • Heart disease
  • Family history of kidney disease, diabetes, or hypertension
  • Being African-American, Native American, or Asian-American
  • Sedentary lifestyle
  • Being 60 years of age or older
  • Any history of acute kidney injury (AKI)

Symptoms of Kidney Disease

Kidney Disease Symptoms

As mentioned before, you may not experience symptoms until the majority of your kidney function has been lost.

However, symptoms of CKD may include:

  • Nausea
  • Vomiting
  • Loss of appetite
  • Shortness of breath
  • Fatigue
  • Weakness
  • Less frequent urination
  • Changes in mental status
  • Muscle cramping
  • Swelling at the feet, ankles, hands, and even face
  • Itching
  • Uncontrolled blood pressure

Diagnosis & Stages of Kidney Disease

CKD is diagnosed with blood and urine testing. Your primary care physician may test your kidney health routinely if you present with any of the risk factors noted above.

The stages of kidney disease are listed in the table below.

Stage of Chronic Kidney Disease

Kidney Health Status

Estimated Glomerular Filtration Rate (eGFR)

Stage 1

Kidney damage with normal kidney function

90 and higher

Stage 2

Kidney damage with mild function loss

60 – 89

Stage 3a

Mild to moderate kidney damage

45 – 59

Stage 3b

Moderate to severe kidney function

30 – 45

Stage 4

Severe loss of kidney function

15 – 29

Stage 5

Kidney failure

Under 15

An estimated GFR (eGFR) is calculated using the serum creatinine level. To confirm a diagnosis of kidney disease, a test must be done at two separate times.

It’s important to note that the GFR will decline naturally in the aging process.

In a urinalysis, testing for albuminuria can also show the progression of CKD.

Prognosis of CKD by GFR

Source: Quick Reference Guide on Kidney Disease Screening. National Kidney Foundation. https://www.kidney.org/kidneydisease/siemens_hcp_quickreference. Accessed September 12, 2022.

Treatment for Kidney Disease

While CKD is currently incurable, there are many areas of treatment in managing the disease. Treating kidney disease when first diagnosed can also help in delaying or stopping the progression of the disease.

Kidney Disease Diet

One of the most common first steps in treating CKD is changes to the diet.

Depending on the stage, cause, lab results, and symptoms of kidney disease, dietary modifications can help in better managing CKD.

Kidney Disease Diet

Low Protein

The National Kidney Foundations’ Kidney Disease Outcomes Quality Initiative (KDOQI) updated their nutritional guidelines in 2020 to include support of a low protein diet in managing CKD.

Following a low protein diet can be a challenge for many, as the average American diet has about 14-16% of their daily intake coming from protein.

Potassium Management

While it was previously believed that a low potassium diet was recommended for CKD management, there is now new information to suggest otherwise.

A more individualized approach is now recommended in finding the amount of potassium each person with CKD needs. This can result in allowing more potassium to be consumed, which has shown benefits in managing blood pressure when paired with a low sodium diet.

Before restricting potassium, you should see a registered dietitian for a comprehensive assessment and discussion of how much potassium you can consume daily.

By partnering with a dietitian, you can more safely manage both kidney disease and weight loss.

Phosphorus Control

Once your kidney function starts to decline, then there’s potential for phosphorus to build up in your body. 

Too much phosphorus can cause problems with your bones, increase your risk for cardiovascular disease, heart attack, stroke, and increase your risk for kidney transplant failure.

However, there are several ways to manage phosphorus with chronic kidney disease. Avoiding all phosphate additives can help in preventing phosphorus absorption. 

Make sure to search ingredient lists for the foods you eat to see if phosphate additives or phosphorus have been added. These will show up on ingredient lists as “phos” and can be listed multiple times on a single label. 

Additives made from phosphates are absorbed 90-100% into the bloodstream, making them particularly dangerous.

If phosphorus remains uncontrolled with diet changes, then a doctor may prescribe a phosphate binder to help prevent phosphorus absorption. 

Fluid Management

Similar to potassium, the amount of fluid recommended for someone with CKD will depend on that individual person. 

In later stages of CKD, edema is a more common complication. (Edema is when fluid is trapped and causes swelling). A fluid restriction may be advised by your healthcare provider in an effort to keep kidney function.

In some cases, however; increasing fluid intake may be advised. Certain kidney diagnoses such as kidney stones, kidney infections, and polycystic kidney disease may mean that you need to consume over 3 liters of fluid every day.

Working with your healthcare team will help you determine the right amount of fluid you should drink each day.

Lifestyle Changes

Certain risk factors for kidney disease are changeable and can lower the risk of or progression of CKD.

Smoking Cessation

One of the first (and best) things that you can do for kidney health is to stop smoking. Smoking increases the risk of end stage kidney failure and increases the need for dialysis. 

The risks of smoking are well known, and stopping smoking can help reduce the risk of CKD and complications.

Kidney Disease Medications

With the kidney doing so many jobs for our body, medications are often prescribed for kidney disease to help take over certain jobs that your kidneys can no longer do.

Many people with CKD are prescribed blood pressure medication such as angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs).

For people with diabetes, blood sugar management is very important in keeping kidneys as healthy as possible. Certain types of blood sugar medications, including insulin, may be prescribed.

It’s important to discuss all concerns about medications with your doctor.

Kidney Disease & Dialysis

Dialysis for Kidney Disease

Dialysis is the treatment method if you have end stage kidney failure.

Once a kidney is below 15% function, then you qualify for starting dialysis. 

The process of dialysis includes cleaning the body of toxin buildup that the kidneys can no longer do themselves.

The toxin removal can be done either by:

  1. cleaning through the blood
  2. using the peritoneal (abdominal) cavity

There are several options for dialysis treatment. The most important factor in deciding treatment is understanding which one is best for you and your lifestyle.

Transplant for Kidney Disease

Transplant is considered the “gold standard” for end stage kidney failure treatment. You can apply to be on the kidney transplant waiting list if your kidney function is at or below 20%.

The average waiting time for a kidney transplant is approximately 3 to 5 years, so it’s important to get on the waitlist as soon as possible. Once on the waitlist, monthly blood tests will be done to monitor your kidney function.

After a kidney transplant, a transplant team will follow up and closely monitor your kidney function. There will be life-long anti-rejection medications that will need to be taken to prevent the kidney from being rejected by your body.

Kidney Disease and Weight Loss

As several of the symptoms of kidney disease relate to how much we eat (for example, feeling nauseous or vomiting can lead to a low appetite), weight loss is often an expected result.

While weight loss can be good for some, it’s important to know that there are healthy ways and unhealthy ways when it comes to weight loss with kidney disease.

Healthy Weight Loss with Kidney Disease

For those with a overweight or obese body mass index (BMI), your doctor may encourage some weight loss to help manage your kidney disease.

Healthy weight loss is generally seen as weight loss of one to two pounds per week. For those with over 100 pounds of weight to lose, aiming for approximately 1% weight loss per week may be acceptable. 

Benefits of Kidney Disease and Weight Loss

Intentional weight loss has been shown to help preserve kidney function for those that have type 2 diabetes and kidney disease. 

Other benefits that have been found with weight loss for kidney disease include less protein in the urine (proteinuria) and lower systolic blood pressure.

Unhealthy Weight Loss with Kidney Disease

While there are some benefits of weight loss with kidney disease, there is also a risk of losing the wrong kind of weight.

If weight loss happens too quickly or unintentionally, then it may lead to other health complications.

Sarcopenia is when a person loses muscle mass. This happens with the elderly but can also happen in people with serious health concerns such as cancer, heart failure, and CKD.

Another term for unhealthy weight loss with kidney disease is protein-energy wasting (PEW). This term refers to the body using up its protein stores from muscles in order to keep up with energy needs.

Protein-energy wasting is quite common with CKD, especially those with end stage kidney failure. In one article, they found that 54% of a group of dialysis patients fell into the classification of PEW.

For other stages of kidney disease, weight loss to the extent of PEW grew from less than 2% of stages 1-2 to 11-46% in stages 3-5.

Unhealthy Weight Loss

Risks of Weight Loss with Kidney Disease

Weight loss, when unintentional, can increase risk factors for other health concerns.

Kidney disease is a highly active state for the body, so more calories are needed to keep up energy levels.

Uremia, inflammation, and autoimmune causes of kidney disease all contribute towards a higher level of calorie needs.

When experiencing unintentional weight loss, it is important to discuss your current nutritional state with your doctor and dietitian. 

If you don’t have a dietitian, then you may be able to ask your doctor for a referral to one so that you have additional support in preventing further unintentional weight loss.

Significant Weight Loss

Significant weight loss is defined as weight loss exceeding in the following ranges:

Time Period

Amount of Weight Loss (%)

1 week / 7 days

>2%

1 month

>5%

3 months

>7.5%

6 months

>10%

1 year / 12 months

>20%

It’s defined as significant weight loss if you’re losing weight at or above these ranges. It’s important to discuss your rate of weight loss with your doctor and healthcare team to ensure you are not at risk of malnutrition. 

Fluid Weight Loss with Kidney Disease

It’s important to know that weight loss or weight gain and kidney disease may be connected due to fluid balance.

The kidneys are responsible for making urine and controlling blood pressure. The amount of urine you make or don’t make is dependent on your kidney function, salt intake, and fluid balance.

Diet Changes for Kidney Disease Weight Loss

You may experience drastic weight loss in the beginning if your diet changes include either cutting down on salt or cutting back on carbohydrates. 

However, once your body adjusts to these changes, your weight loss will gradually slow down. The initial weight loss you’ve experienced is water weight. 

The water weight has been released by not having as much salt in your diet or by the use of carbohydrate stores in your body (which release water when they are used by your body). 

Medications for Weight Loss with Kidney Disease

Medications

Many people with kidney disease require the use of diuretics.

These help to control blood pressure by creating more urine and helping to release extra fluid buildup.

It’s very important to take medications exactly as prescribed by your doctor.

Not following directions can lead to serious problems and health concerns.

Dialysis

In dialysis, excess fluids are taken out of the body. Your weight is measured both before and after a dialysis treatment to measure the amount of fluid that was removed.

It’s important to know that this is not actual weight loss. Dialysis weight loss is the removal of the extra fluid that was collecting in your body due to the kidney’s inability to remove it on its own.

Actual weight is calculated based on the trends of the dialysis treatment weights as well as blood pressure and electrolyte balance

Your nephrologist and dialysis healthcare team, your nurse, and dietitian will monitor your weight for true weight changes.

Tips for Safe Weight Loss with Kidney Disease

If you have been encouraged by your healthcare provider to lose weight, here are some steps you can take to safely manage both your kidney disease and weight loss.

Walk

Try getting in more steps if you’re able to walk! Walking is a great way to lose weight and create a consistent exercise routine that is not hard on the body.

If you find walking to be unappealing, then try pairing it with an enjoyable hobby. Maybe you enjoy walking while listening to old radio shows. You may look forward to your exercise so you can listen to more episodes!

Eat More Fruits and Vegetables

Many think they need to cut back on fruits and vegetables due to the potassium, but this is not always the case. Plus, there are plenty of low-potassium fruits and vegetables to choose from. Fruits and vegetables are low in calories but have a lot of nutritional value.

Choose Snacks Wisely

If you enjoy having a snack between your meals, then make sure you are choosing something that will still support your kidney disease and weight loss goals!

Try some low-sodium snacks (less than 240 mg of sodium) that you can find online or in the grocery store.

Another tip to finding snacks for kidney disease and weight loss is to focus on snacks that have 3 grams or more of fiber.

Hydrate Appropriately

While kidney disease may change how much you should be drinking every day, it’s important to know what your right fluid goal is and aim for that each day.

Many people are consistently dehydrated from not drinking enough, and the risk of dehydration increases as we get older.

Ask your doctor if you need to be on a fluid restriction, or find out if you have a fluid goal to aim for. Only your doctor and dietitian can tell you how much fluid you should be drinking each day.

How to Safely Gain Weight with Kidney Disease

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Add in Heart-healthy Fats

There are plenty of healthy fat sources in our diet that can add in calories! Fat has the highest calorie per gram volume compared to carbohydrates and protein, so adding in a few tablespoons can do a ton for weight gain for kidney disease.

Try adding in some coconut oil* to your morning oatmeal – just a teaspoon will do the trick! If you’re not a fan of coconut oil, then you can use flaxseed oil* or ground flaxseeds.* Just be sure that the flaxseed is ground and not whole.

When roasting up some veggies, add an extra tablespoon of avocado or olive oil. Roasted vegetables, whether low or high potassium, are a great part of a kidney-friendly diet.

Calorie-rich Shakes

To boost the calories in your smoothies, try adding in some ground flaxseed or chia seeds. One ounce (about two tablespoons) of chia seeds adds on an extra 140 calories for only 115 milligrams of potassium. 

Keep in mind that seeds do include protein – about 5 grams – so it’s important to factor that into your daily protein needs. Try canned coconut milk for the milk base for your shakes or other recipes. It has a high level of calories per cup.

Kidney-friendly Nutritional Shake

The nutrition company Abbott makes a kidney-friendly nutritional shake called Suplena* that is low in protein, potassium, sodium, and phosphorus. If you cannot maintain your weight with food, then consult with your dietitian or doctor about adding Suplena to your diet.

If you are on dialysis and need to gain weight, Abbott also has a dialysis-specific product called Nepro* that has more protein you need due to dialysis.

You can ask your dialysis dietitian or nephrologist about the potential benefits of adding this to your dialysis treatment plan.

Skip the Protein Powders

In 2020, the Kidney Disease Outcomes Quality Initiative (KDIGO) from the National Kidney Foundation recommended that those with kidney disease not follow a high protein diet

In later stages of kidney disease (not on dialysis), protein recommendations can be as low as 0.4 grams per kilogram of body weight.

To put that into perspective, someone weighing 100 pounds would be recommended to only consume about 18 grams of protein a day. 

When it comes to safely adding calories, do not add protein powders if you have kidney disease. This may prevent weight loss but can harm your kidneys. 

Kidney Disease and Weight Loss Summary

When it comes to kidney disease and weight loss, there is a safe way and an unsafe way to lose weight.

If your doctor and healthcare team is encouraging you to lose weight for your kidney health, be sure it’s slow and steady to keep your kidneys healthy. Working with a dietitian is a great way to help make sure everything goes smoothly for your weight loss goals. 

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