Body Mass Index (BMI)
Some transplant centers require a certain body mass index (BMI) before transplant. BMI is an estimate of your body fat based on your height and weight. A BMI greater than 30 kg/m2 indicates obesity, which has been linked to an increased risk for infection, poor wound healing, and rejection of the donated kidney. If your transplant center has asked you to lose weight before your transplant, you have to approach weight loss with great caution. Even though you may have a high BMI, your body can still be lacking important nutrients. This is especially true if you have had kidney disease for a long time or have been on dialysis. Body weight and BMI are not the only measures of good nutrition.
If you are asked to lose weight, then the next step is to meet with the registered dietitian/nutritionist (RDN) at your transplant center. If no one mentions a referral to the RDN, then please ask for one. The RDN will review your lab results, medications and supplements, current diet, and weight history. Based on this information, you will receive guidance for losing weight in a healthy manner. This means that you will lose weight slowly, and without losing out on important nutrients. Remember that you need to stay healthy for your surgery, and extreme weight loss can put you at great risk for problems. Crash diets that are too low in calories can be very dangerous, and especially for people with kidney disease – they are not worth the risk! Exercise always helps with healthy weight loss, so you should discuss your options with your doctor.
You may be advised to have weight loss surgery before your transplant, but this must be decided very carefully. Be aware that certain surgeries decrease the amount of nutrients you can absorb. This can then lead to oxalates building up in your body. Oxalates are chemicals that cause kidney stones and kidney damage. Having a problem with oxalates may risk your eligibility for transplant. You may still need weight loss surgery, but there are surgery options that will not interfere as much with your overall health. Please discuss all options very carefully with your transplant center, and get extra opinions before having any weight loss surgery.
Weight Gain After Transplant
Weight gain after kidney transplant can happen for many reasons. Patients who once needed many diet restrictions can now eat a greater variety of foods. They also have a better appetite, which is a positive sign of good health. But some medications can make it easier to gain weight, and may also increase your appetite too much. Weight gain can then lead to diabetes and heart disease. So you need to limit your portions, keep a healthy eating pattern (don’t skip meals and don’t get stuffed), eat lots of vegetables, fruits, and whole grains, along with low fat dairy products and meats. Avoid processed foods and drinks that are high in fat, sugar, and sodium (salt), and read labels carefully. Stay well-hydrated with water, in an amount recommended by your transplant center. The same weight loss principles apply after transplant as they did before transplant -- slow and steady weight loss with guidance from your RDN, along with exercise.