Going onto renal dialysis changes everything about a person's life, not the least of which is diet. For most people, dialysis comes after months, or perhaps years, of slowly failing kidney function as a by-product of diabetes, congestive heart failure, or a kidney-specific disease, and proper diet has been an important part of health care during that entire time.

But, with the onset of dialysis treatment, big changes in food recommendations take place. The nutritional needs for dialysis patients differ from any other group; while the rest of the world clamors for heart healthy, low fat foods with an abundance of fresh fruits and vegetables and at least eight glasses of fresh, pure water a day, the watchwords for those undergoing dialysis are calories and protein.

Patients must strive to eat enough to keep body weight steady, often in spite of declining appetite. At the same time, they must restrict sodium, potassium, phosphorous and liquid intake. Consultation with a nutritionist is imperative; recommendations will differ according to the type of dialysis and the patient's overall health.

CALORIES must be sufficient to prevent muscle wasting. Depending on the size of the person, their beginning weight, and their ideal "dry weight" (without fluid retention) a physician or dietitian may establish a minimum daily calorie requirement.

PROTEIN is the cornerstone of the dietary plan, and most of it should come from foods with an abundance of amino acids, such as meat, eggs, and some dairy products. Other foods do contain protein, but without the amino acids the protein is less likely to be converted to muscle and to be passed in urine, placing stress on already struggling kidneys. Some traditional sources of protein actually contain other substances that can cause problems on a renal diet and should be avoided; these include dried beans, nuts and nut butters.

For a person on dialysis, protein requirements skyrocket. To stay healthy, physicians recommend a minimum of 1.5 to 2 grams of protein per kilogram of "dry weight"--that's the ideal weight without fluid retention.

A good guideline is to eat about 25% of the protein requirement at each meal and use snacks and supplements to meet the total requirement. Dietitians encourage meat at every meal, frequent egg dishes, and high protein supplements.

POTASSIUM count becomes crucial -- no more than 2 to 3 grams per day, according to the advice of the patient's physician. Since this is currently not a requirement for listing in the nutritional information on food packages, a list of high and low potassium foods from a dietitian or a comprehensive book on nutrition is a valuable resource.

SODIUM, probably already restricted in the months leading up to dialysis, also is crucial. While still limited, sodium is one of the minerals removed by the dializing process, so guidelines might be modified upward. Depending on the particular medical condition, a limit of 2 to 3 grams daily will be given.

DAIRY PRODUCTS, while an important source of high quality protein, need to be limited because of the phosphorous content, perhaps to 8 oz per day including milk, cheese, and butter. Allowable cheeses include parmesan and other white, low-sodium varieties. Non-dairy substitutes work well on cereal, in coffee, and in desserts.

PHOSPHOROUS is an important element for good bone production, and most people can handle any excess; their bodies simply eliminate it. But that's not true for the dialysis patient, so high phosphorous foods have to be avoided. Itchy skin is an early sign of phosphorous building up in the blood stream. Forbidden foods include oatmeal, bran cereals, brown rice, dried beans and lentils, organ meats, salmon and sardines, chocolate and cola drinks.

While it seems that there are a lot of "do not eat" rules, it is possible to have a varied and delicious diet from the list of foods that are acceptable and healthy for people undergoing dialysis. Yes, choices must be made, but many people live quite well for decades while having dialysis several times a week.

NOTE: THESE ARE GENERAL GUIDELINES. SPECIFIC MENUS OR FOOD CHOICES SHOULD BE MADE ON THE RECOMMENDATION OF YOUR NUTRITIONIST OR PHYSICIAN.

Breakfast can be a serving of steak or burger and eggs (an omelet made with three whites and one yoke, perhaps), fruit selected from the low potassium list, a slice of toast with jam.

Wheat, rice, and corn cereals work, either hot or cold. Potatoes can be included RARELY if they have been soaked overnight before cooking. (The foam that rises to the top of the soaking pot is the potassium leaching out of the potatoes into the water, which must be discarded.) White rice (not brown) can take the place of hash browns.

Lunches and dinners should sliced roast beef, poultry, well-rinsed tuna, or fish with a salad of iceberg lettuce (lower potassium than loose leaf) with a selection of carefully chosen fresh or canned vegetables. A fruit salad in a base of non-dairy whipped topping, made with canned fruits.

In addition to the liquid supplements available especially for dialysis patients (high calorie, high protein, low sodium and potassium blends) snacks can include selected fruits, a vegetable snack tray with seasoned sour cream, a mix of rice chex, corn chex, wheat chex and popcorn drizzled with melted butter seasoned with garlic, onion, chili powder and parmesan cheese.

Unless diabetes is a consideration, calories can also come from hard candies and other sugar-rich foods that don't contain sodium, potassium or phosphorous.