By Michelle Trahan, MS, RD, LD

The first thing that comes to mind when someone mentions they are on a diet is weight loss. However, a diet is whatever a person eats, regardless if the person sets a weight loss goal. For people with kidney disease, the word diet is used almost daily. There are several restrictions involved in a renal diet, such as potassium, phosphorus, sodium, calcium and fluids. If you have kidney disease, relying on fad diets for weight loss may put you at high risk for serious medical problems.

First of all, everyone is different. Assuming that one weight loss plan works for everyone is misleading. Even your basic renal diet is individualized to your own needs. There are five stages of kidney disease and your diet usually depends on what stage you are currently in. A person with kidney disease who is not on dialysis may need to restrict protein in their diet. However, once someone starts dialysis, the protein need changes and it is important to increase protein intake. The same is true with other nutrients, such as sodium, phosphorus and potassium. With that being said, let’s look at a few current popular weight loss fads.

The Atkins’ Diet

These days, the Atkins’ Diet¹ seems to be part of everyone’s vocabulary – so let’s start with this one. Many people like this diet because they can eat a lot of meat and fat that most diets do not allow. The goal of this diet is to lower carbohydrate intake. All carbohydrates are converted to glucose when absorbed by the body. Glucose is the body’s main source of fuel and is either immediately used for energy or it is stored as glycogen in the liver and muscles for later use. Some glucose is stored as fat. The goal of the Atkins’ Diet is to limit the production of glucose. In turn, the body resorts to using stored glycogen as its energy source. Once glycogen stores are depleted, the body starts breaking down fat stores for fuel. This process is called ketosis. The body then uses keto acids as an energy source. When large amounts of keto acids are present, they can cause nausea, fatigue, bad breath, dizziness and abnormal heart rhythms (due to electrolyte imbalances). High-protein diets in people with kidney disease can potentially speed up the progression of their disease. High-protein, low-carbohydrate diets may also increase blood levels of phosphorus, potassium and urea. This diet could be very dangerous if you have kidney disease.

As a general rule, if a diet excludes any of the basic food groups, it will most lack vital nutrients. Limiting carbohydrates is always a good idea when it comes to weight loss. However, you should consume at least 50 percent of your calories from carbohydrates and no more than 30 percent of your calories from fat.

Sugar Busters Diet

Another popular diet is the Sugar Busters Diet². It is always a good idea to avoid sugar and sweets when trying to lose weight. This diet allows carbohydrates, however, it limits you to low glycemic index carbohydrates such as whole grains, beans, some fruits and some vegetables. The glycemic index is a method of classifying foods according to its ability to raise blood sugar levels. For example, simple sugars like candy will raise blood sugar levels faster than whole grains or vegetables (low glycemic foods). The theory is that when foods with a high glycemic index are consumed, more insulin is secreted by the pancreas. The increase in insulin secretion helps to increase fat storage. Many foods with a low glycemic index, such as whole wheat bread, brown rice and bran cereals, are high in potassium and phosphorus. Refined grains, such as white bread and white rice, which have a higher glycemic index, are better choices for people with kidney disease because they are lower in phosphorus and potassium. Some vegetables and fruits recommended as healthy low-calorie foods may also contain large amounts of potassium and phosphorus. The potassium and phosphorus content of a particular food is far more important that its glycemic index. Remember, too much potassium and phosphorus may be harmful if you have kidney disease.

South Beach Diet

The South Beach Diet³ has three phases. Phase 1, which lasts 14 days, allows lean meats, low-fat cheese, low-fat dairy products and nuts. It also allows “good fats,” such as olive oil, canola oil and peanut oil. It omits all starches, such as bread, rice, potatoes, fruit, baked goods, cookies and cakes. This phase only allows vegetables with the highest fiber content and lowest sugar content. Again, this phase incorporates a lot of protein and very few calories come from vegetables. Meats, dairy products and fats provide the majority of the calories. High-protein diets are avoided in kidney disease patients due to the possibility of progressing kidney failure. Phase 2 allows you to reintroduce whole grain breads, pastas, cereals and fruit. However, you have to pick and choose which ones you want to eat. You can’t have all of them all the time. This phase lasts until your weight goal is reached. This sounds very healthy for the general population, but with kidney disease this would be a diet very high in phosphorus and potassium. Phase 3 of the South Beach Diet is the maintenance phase. This is how you would eat the rest of your life.

Renal-Friendly Tips for Weight Loss

Fad diets may not be appropriate for the majority of kidney disease patients. Many foods usually considered healthy can be harmful to those with decreased kidney function. Each weight loss plan should be supervised by a registered dietitian. A good diet plan will be one you can continue for the rest of your life. These tips will help you achieve a healthy, renal-friendly diet.

• Weight loss requires eating fewer calories per day than the body uses. In order to lose 1/2 to 1 lb. of fat per week, a person needs to consume 250 to 500 fewer calories per day than the body needs. By using your height, weight and activity level, a dietitian can calculate how many calories per day would promote weight loss.

• Make sure you set realistic goals. Remember, you did not gain all the extra weight over night, so don’t expect to lose it so quickly.

• Always eat a variety of foods. Omitting a food group will put you at risk for vitamin and nutrient deficiencies. It may also provide an abundance of nutrients that could harm your body when your kidneys are not working properly.

• Portion control is the key when it comes to weight loss. If you are eating foods high in calories, limit the serving size.

• Try to stay away from empty calories, such as candy, sodas and sugar.

• Talk to your doctor about exercising. The weight will come off easier if you are burning extra calories each day – try walking, swimming or biking. Remember, you have to make diet and exercise a part of your life, so do something you will enjoy.

Losing excess body weight will definitely improve your health. Better blood pressure control, healthier blood cholesterol levels, and better blood sugar management are just some of the benefits of weight loss. Unfortunately, there are no quick fixes when it comes to weight loss. Always think of your health first when you are dieting. Your weight loss program should help you lose weight without putting you at risk for other medical problems. Do not fall for the quick fixes – your health is too important!

References:

1. Atkins, R.C., and Gare, F. Dr Atkins’ New Diet Cookbook. M. Evans and Company, Inc., New York, New York, 1997

2. Steward, H.L., Bethea, M.C., Andrews, S.S., Balart, L.A. Sugar Busters!; Cut Sugar to Trim Fat. Ballantine Publishing Group, New York, 1998

3. Agatston, A.S. The South Beach Diet. Rodale, 2003

Michelle Trahan, MS, RD, LD, has been a renal dietitian for 8 years working with hemodialysis and peritoneal dialysis patients. She currently works for Genzyme Therapeutics, Renagel Sales, as the Gulf Coast Regional Clinical Consultant.

The information contained herein is intended for educational purposes only. It is not intended and should not be construed as the delivery of medical care. Persons requiring diagnosis or treatment, or those with specific questions, are urged to contact their local healthcare provider for appropriate care.

This article originally appeared in the September/October 2005 issue of Kidney Beginnings: The Magazine, Vol. 4, No. 3.