If you or a loved one are nearing kidney failure or are already on dialysis and considering a kidney transplant, it’s important to know how your weight and body mass index (BMI) can affect your chances of transplant eligibility and a successful outcome. In a presentation hosted by the American Kidney Fund, Dr. Brent Miller, MD, Professor of Medicine and Clinical Chief of Nephrology at the Indiana University School of Medicine, discussed:

• Preparing for a kidney transplant as it relates to weight and BMI
• Post-surgery considerations 
• Strategies to help you reach and maintain a healthy weight pre-and post-transplant

Preparing for a kidney transplant

While heavier people appear to do better on dialysis than thinner people, research shows that obesity at the time of kidney transplant surgery is associated with poor outcomes, such as:

• Wound healing complications
• Higher organ rejection rates
• Lower kidney function
• Lower survival rates

Though parameters may differ among various surgeons and transplant centers, most will not even place a patient on a kidney transplant waiting list if their BMI is over 40.

Post-surgery considerations

In the U.S., the average kidney transplant recipient gains 20 to 30 pounds within a year following the surgery. There are no simple answers to why this happens, said Dr. Miller, but his experience with patients suggests that the result is a combination of factors that include:

• Diet
• Physical activity
• Medications
• Metabolism

Diet

The diet factor has a couple of components. Your post-transplant diet should be roughly the opposite of the diet you followed while on dialysis. The dialysis “renal diet” is low in protein and high in fats and carbohydrates. Once you have a working kidney, however, this diet no longer serves you. 

The other component is psychological. Many transplant recipients, suddenly freed from the restrictions of the renal diet, begin eating many, most, or all of the foods that they’ve been craving for the past few years. Once off of dialysis, your appetite may improve, which may contribute to this, as well.

Physical activity

Physical activity is critical to good health. Being overweight but physically active is better than being a “normal” weight and sedentary. According to Dr. Miller, even 4,000 steps a day will have a beneficial effect on your health. Physical activity can help you live longer and reduces your likelihood of becoming disabled as you age. Dr. Miller also suggests adding some type of resistance training for about 15 minutes a day, two to three times a week.

Medications

Prednisone and other steroids are known to be appetite stimulants. Tacrolimus (Prograf), an immunosuppressant drug that helps prevent organ rejection, can also cause you to become diabetogenic, which means that the drug produces a constant elevation of your blood glucose. Nearly 20% of transplant patients who were not diabetic before the surgery become diabetic within five years of their kidney transplant.

Metabolism

Your metabolism while on dialysis is very different from your metabolism off dialysis. With a working kidney, you don’t need as many calories. Dr. Miller likens the body to a car and the kidney to an engine. You don’t need as much gas to run an efficient engine, he said, as you do to run an inefficient one.

Strategies to maintain a healthy weight

There are no pat answers for patients with kidney failure for achieving and maintaining a healthy weight and BMI. Dr. Miller recommends working closely with your dietician and physician, both before and after a transplant, to create a customized care plan regarding:

• Types of food 
• Number of calories
• Physical activity types and duration
• Medication management
• Observation to prevent and/or control diabetes

At the very least, he said, the dictum “eat less, move more” is a helpful guideline.

*American Kidney Fund. (2019, June 26). Healthy weight pre and post-kidney transplant. https://www.kidneyfund.org/training/webinars/healthy-weight-kidney-transplant.html