Dieting and Chronic Kidney Disease

A lot of people with declining kidneys have a “wake-up call” and decide to start eating a healthy diet. There’s a lot of guilt that comes with kidney disease. Many people feel as if it’s their fault. As a dietitian, I find that people pursue very extreme diets after their diagnosis. These diets often make the kidneys worse and can cause further damage. If you have declining kidney function, you may be asking yourself some questions: should I go on a diet? Should I lose weight? Should I fast? Should I just eat salads? Should I follow a low carb diet? This article will help answer some of these questions.

Extreme Diets and Kidney Disease

In general, people need about 2000 calories per day to survive and maintain their weight. A young tall man could need about 4000 calories, and a shorter older woman may need as low as 1400 calories. People with kidney disease also need more calories as their bodies are in a hypermetabolic state. Doing very extreme calorie restrictions of over 300 calories below needs may be damaging. The damage that happens is internal as it interrupts your body’s regulatory systems. Here's how:

• Your body can start breaking down muscle mass (muscle is a protein and easily can turn to sugar) releasing cell contents into the blood. This can raise blood acidity.

  • This may also make insulin resistance worse because losing muscle is very unhealthy.

• Your body may change to ketosis for energy where the fat molecules turn to ketones for fuel. This can also raise blood acidity.

• Acidic blood, or metabolic acidosis can cause further damage to the kidneys

• When the muscles break down and the blood turns more acidic, potassium is drawn into the blood making you at very high risk for potassium related heart issues.

  • It’s very important for most people to manage their blood potassium as high potassium can cause cardiac arrest (a very small amount of people have low blood potassium so it’s important to follow the instructions of your doctor or dietitian)

Body Weight and Kidney Disease

When the kidneys decline, there is more to worry about than starting dialysis. Unfortunately, with reduced kidney function, most people don’t make it to dialysis. Dialysis is a lifesaving therapy, and at the same time, can be traumatic for many people to start. This being said, your longevity becomes a top priority, therefore, eating well is very important.

People with an “extra few pounds on” tend to do better than those who are very skinny. It’s almost like you need the extra weight to provide support when your body needs it the most. This is true for anyone - it is good to have some muscle and fat when sick to support you incase your body’s energy and protein needs increase. Regular healthy people should aim for a BMI of 22.5 to 25. People with kidney disease should aim for a BMI of 25-27.

Ketogenic diets and intermittent fasting

Ketogenic diets are diets that contain less than 50 grams of carbohydrates per day. Having such a low carbohydrate intake can cause acidosis and lead to the same problems listed above. As for intermittent fasting, there is not enough research to recommend it for kidney disease (or even diabetics). Most of my patients that fast, in my experience, do have highly acidic blood. I believe that with intermittent fasting, there is also risk for acidosis and muscle breakdown, as we discussed.

In summary, low calorie and pop diets such as intermittent fasting and the ketogenic diet are not recommended for people with kidney disease. These diets may even cause harm and quickly deteriorate kidney function. Make sure to work with a Registered Dietitian and have 3 hearty meals per day or per the individualized recommendations.