Why does Kidney Disease Cause Weight Gain?

Guest Blog by Dr. Nasim Musa Porosh (Consultant Nephrologist)

Kidney disease doesn’t just affect the kidneys, it affects the whole body. In the early stages, it can cause weight loss, while in the later stages it can cause weight gain. These variations are the result of different aspects of kidney disease as it progresses. 

Here is some information to help you understand the issue of kidney disease and weight gain,

The primary task of the kidneys is to maintain the fluid balance in the body. They accomplish this task through increasing or decreasing the amount of fluid excreted in the urine. 

Electrolytes (minerals with an electrical charge) like sodium and potassium are an important component of fluid management. When you eat or drink liquids, the fluid eventually makes its way to the kidneys. 

A complex mechanism of fluid and electrolyte transfers, mediated by hormones and other chemicals, results in the movement of fluid into the kidneys and bladder, from which the urine is excreted. Kidney disease damages these mechanisms.

Early Kidney Disease causing Initial Weight Loss

In the early to middle stages of kidney disease, people often lose body weight. This occurs because the disease causes loss of appetite. Appetite regulation is very complex, but your appetite is affected by chemical compounds in the blood that affect the brain. 

People with kidney disease begin to build up compounds that suppress their appetite. These changes can also alter your sense of taste. Many people begin to avoid protein foods like meat, which can result in muscle wasting. All of these changes can result in weight loss (both fat and muscle).

Late Stage Kidney Disease (Kidney Failure) leading to Excess Weight Gain

Untreated kidney disease will usually progress to complete kidney failure. The kidneys simply stop functioning or function so poorly that they cannot keep with the work of fluid management. Fluid builds up in the tissues, causing swelling and weight gain. 

It is important to recognize that this is water weight, not fat or muscle. 

In fact, many people with severe kidney disease or kidney failure are actually undernourished. The excess swelling can make it difficult to breathe and increase your blood pressure.

Kidney Dialysis & Weight Gain

Dialysis is a medical treatment that takes over the function of the kidneys. One of its primary objectives is to remove excess fluid. You may hear your doctor talk about “dry weight” and “fluid weight.” The first is what your weight is when your blood pressure is under control and there is no excess fluid in your body. Fluid weight is the weight you gain from fluid and foods in the intervals between dialysis treatment. 

To help manage fluid weight, you must follow a strict diet with limited sodium and usually need to restrict your fluid intake as well. After a successful dialysis treatment, your weight will decrease. 

This is why you are always weighed before and after a dialysis treatment.

Weight is an important component of dialysis and kidney disease management. 

Reach out to VIOS

For further discussion on what to expect as you or your family member undergoes the complex journey in kidney dialysis, have a chat with our online and on-call nephrologists.

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