Lesson 10  Diet Therapy

Food is essential to life. To sustain life, the nutrients in food must perform three functions within the body: build tissue, regulate metabolic processes, and provide a source of energy. A proper diet is essential to good health. A well-nourished person is more likely to be well developed, mentally and physically alert, and better able to resist infectious diseases than one who is not well nourished. Proper diet creates a healthier person and extends the years of normal bodily functions. Diet therapy is the application of nutritional science to promote human health and treat disease.


We all eat certain foods for reasons other than good nutrition and health. Our eating patterns develop as part of our cultural and social traditions and are influenced by our life style and life situation. It is important for the nurse to understand factors, which influence food choice and eating patterns.

Social Aspects. Most people prefer to eat with someone, and the patient is probably used to eating meals with his family. In the hospital he is served his food on a tray and left alone. Poor nutrition may be the result.

Emotional Aspects. The patient may feel guilty for not eating all the food served, or may overeat just because the food is there. The patient may overeat because he or she feels sad, lonely, or depressed or may refuse to eat for the same reasons. Certain foods may be considered "for babies." Some foods may be used as rewards."

Food Fads and Fallacies. These are scientifically unsubstantiated, misleading notions or beliefs about certain foods that may persist for a time in a given community or society. Many people follow fad diets or the practice of eating only certain foods. Food fads fall into four basic groups: Food cures, harmful foods, food combinations that restore health or reduce weight, and natural foods that meet body needs and prevent disease.

Financial Considerations. The patient's financial status has a great bearing on eating patterns. Most people in the United States can afford a diet, which includes a variety of foods and a sufficient number of calories. However, many Americans consume an excessive amount of fat and sodium. Excess fat consumption has been shown to be related to the development of heart disease. Excess sodium consumption may be a problem for some patients with hypertension. Many Americans with lower incomes consume a great percentage of their calories in the form of fat, since fat is the least expensive nutrient (when compared to carbohydrate and protein) and provides for greater satiety (feeling of "fullness" after eating) than both carbohydrate and protein."

Physical Condition. The patient may not feel well enough or strong enough to eat. Encourage the patient to eat without forcing him to do so. Encourage him to feed himself, so that he will not feel helpless.

Cultural Heritage. Food preferences are closely tied to culture and religion. Understanding these preferences will enable you to assist the patient in reaching and maintaining good nutritional health.

Mexican-Americans eat tortillas, rice and beans with most meals. Meats are heavily spiced, and often chopped or ground. Adults use limited amounts of milk and milk products, but enjoy sweet baked desserts, sweetened beverages such as hot chocolate and carbonated drinks.

Puerto Ricans tend to adopt American food habits. Traditional meals include white rice cooked with lard and served with beans. Some practice the "hot-cold" theory in the treatment of illness with food.

Cuban-Americans use rice and beans extensively and meat is served if income is sufficient. Children drink milk but adults use milk only in coffee.


Cultural and religious practices are often intertwined. Many people refrain from eating certain foods, or eat specific foods in certain combinations, because of their religious beliefs. There are some major religious customs related to diet that, as a nurse, you must be aware of.

Hindu. Most Hindus are lacto-ovo vegetarians. They do not use stimulants such as alcohol or coffee.

Moslem (Islam). Meat and poultry must be slaughtered according to strict rules. Moslems do not eat pork or pork products. They do not drink alcoholic beverages. They do drink tea. Moslems fast for one month each year, avoiding food from dawn until after dark.

Jewish (Orthodox). Orthodox Jews do not eat pork, shellfish, or scavenger fish. They do eat beef, veal, lamb, mutton, goat, venison, chicken, turkey, goose, and pheasant. Meat must be slaughtered by a ritual method. Meat and milk may not be served at the same meal. Meat and dairy foods must be prepared in separate containers and with separate utensils. Certain days of fasting are observed, but a rabbi may excuse an elderly or ill patient.

Mormon. Mormons do not drink alcohol, coffee, tea, or caffeine containing carbonated beverages. They do not use extremely hot or cold foods (no ice in beverages).

Roman Catholic. Catholics may voluntarily abstain from eating meat on Fridays and during Lent. They do not eat or drink (except water) before taking Holy Communion. They fast on Good Friday and Ash Wednesday, but a priest may excuse the elderly or an ill patient.

Seventh Day Adventists. Seventh Day Adventists do not drink alcohol, coffee, or tea. They are usually lacto-ovo vegetarians.


Because of the dangers of too much animal protein resulting in health problems or for ecological reasons, many people have chosen to be vegetarians. They do not eat any type of meat. Some vegetarian diets are stricter than others.

The greatest concern in the vegetarian diet is attaining adequate amounts of complete protein. This is easy in the lacto-ovo vegetarian diet, but difficult for the vegan. The most efficient protein available is that found in dairy products, eggs, and fish. Among the sources of protein that can be used most efficiently by the body, meat actually ranks third. The second best supply of efficient protein is legumes, soybeans, nuts, and brown rice.

Vegans should eat at least two of the following at the same meal in order to provide all essential amino acids:

Whole-wheat grains and cereals are preferred in vegetarian diets. Other foods must be added to the protein sources to supply vitamins and minerals. Vegetarian diets are often deficient in calcium, iron, zinc, vitamin D, iodine, and riboflavin. Vitamin B12 is probably missing entirely. Supplements of these substances often need to be taken.


The meals served in a hospital cannot accommodate all social and cultural variations in food habits. However, meals can be individualized to assure that patients are provided with foods that are acceptable to them, but still within the restrictions of their diet. A meal, no matter how carefully planned, serves its purpose only if it is eaten. Many factors alter a patient's eating patterns during hospitalization.


Nutrition plays an important part in a patient's overall condition. A person who is ill may need help in meeting his basic needs for adequate nutrition. Certain factors in illness may alter food intake.



Mealtime is an important event in the patient's long day and the patient's diet is an integral part of the total treatment plan. Certain nursing interventions may help the patient meet his or her nutritional needs.


The practical nurse should be familiar with the diet prescription and its therapeutic purpose. Although individual trays are carefully checked before leaving the Nutrition Care Division, mistakes can happen. Examine each tray with the patient's specific diet in mind. You should be able to recognize each type of diet.

You should relate the diet to body function and the condition being treated. For example, a low fat diet is usually the first step in treating patients with elevated blood lipids (hyperlipidemia). Hyperlipidemia may be caused by improper diet or it may have a secondary cause, such as hypothyroidism or renal failure. Untreated hyperlipidemia can lead to coronary heart disease.

Be able to explain the general principles of the diet to the patient, and obtain the patient's cooperation.

Help plan for the patient's continued care.


Nutritional support is fundamental, whether the patient has an acute illness or faces chronic disease and its treatment. Frequently, it is the primary therapy in itself. The registered dietitian, along with the physician, carries the major responsibility for the patient's nutritional care. The nurse, and other primary care practitioners provide essential support. Valid nutritional care must be planned on identified personal needs and goals of the individual patient. We should not lose sight of the reasons for therapeutic diets.

To Maintain or Improve Nutritional Status. The stereotypical all-American family with two parents and two children eating three balanced meals each day with a ban on snacks is no longer a common reality. Widespread societal changes include an increase in the number of women in the work force and families who rely on food items and cooking methods that save time, space, and labor. The "snack" is clearly a significant component of foods consumed. A therapeutic diet may be planned to promote foods that contribute to nutritional adequacy.

To Improve Nutritional Deficiencies. Dietary surveys have shown that approximately one third of the US population lives on diets with less than the optimal amounts of various nutrients. Such nutritionally deficient persons are limited in physical work capacity, immune system function, and mental activity. They lack the nutritional reserves to meet any added physiologic or metabolic demands from injury or illness, or to sustain fetal development during pregnancy.

To Maintain, Increase, or Decrease Body Weight. Despite the growing interest in physical fitness, one out of every four Americans is on a weight reduction diet. Only 5 percent of these dieters manage to maintain their weight at the new lower level after such a diet. The basic cause is an underlying energy imbalance: more energy intake as food than energy output as basal metabolic needs and physical activity. Being underweight is a less common problem in the US. It is usually associated with poor living conditions or long-term disease. Resistance to infection is lowered and strength is reduced. Other causes for a person being underweight are self-imposed eating disorders, malabsorption resulting from a diseased gastrointestinal tract, hyperthyroidism, and increased physical activity without a corresponding increase in food intake.

To Alleviate Stress to Certain Organs or to the Whole Body.

General functional disorders of the intestine may be caused by irritation of the mucous membrane. Symptoms vary between constipation and diarrhea. Dietary measures are designed to provide optimal nutrition and regulate bowel motility. There should be additional amounts of fruits, vegetables, and whole grains. The fiber content may need to be decreased during periods of diarrhea or excessive flatulence.

Organic diseases of the intestine fall into three general groups: anatomic changes, malabsorption syndromes, and inflammatory bowel disease with infectious mucosal changes.

To Eliminate Food Substances to Which the Patient may be Allergic. There are three basic approaches to the diagnosis and treatment of food allergies: clinical assessment, laboratory tests, and dietary manipulation. Diet therapy is individualized.

To Adjust Diet Composition. A therapeutic diet may be ordered to aid digestion, metabolism, or excretion of certain nutrients or substances.


Clear Liquid Diet. This diet is indicated for the postoperative patient's first feeding when it is necessary to fully ascertain return of gastrointestinal function. It may also be used during periods of acute illness, in cases of food intolerance, and to reduce colon fecal matter for diagnostic procedures.

The diet is limited to fat-free broth or bouillon, flavored gelatin, water, fruit drinks without pulp, fruit ice, PopsiclesŪ, tea, coffee or coffee substitutes, and sugar. No cream or creamers are used. Carbonated beverages may be included when ordered by the physician; however, they are often contraindicated.

The standard menu mat (DA Form 2902-15R) provides approximately 1146 calories. This diet is below the recommended dietary allowances (RDA) for all nutrients tabulated except for Vitamin C (ascorbic acid). If the patient is to be on clear liquids for an extended period of time, the portion sizes should be increased or an accepted enteral formula may be provided.

Full Liquid Diet. This diet is used when a patient is unable to chew or swallow solid food because of extensive oral surgery, facial injuries, esophageal strictures, and carcinomas of the mouth and esophagus. It may be used to transition between a clear liquid and a regular diet for the post-surgical patient.

The diet consists of foods, which are liquid at room or body temperature, and will easily flow through a straw. Included in the full liquid diet are all juices, strained soups, thinned, cooked cereals, custards, ice cream, sherbet, and milk. A high protein beverage is given at breakfast and between meals. Commercially prepared liquid supplements may also be used.

The standard menu mat (DA Form 2902-12-R) provides approximately 2777 calories. This diet is slightly below the RDA in iron for females, and in niacin for men.

Advanced Full Liquid Diet. This diet may be prescribed to meet the nutritive requirements of a patient who must receive a full liquid diet for an extended period of time or who has undergone oral surgery and must have foods, which can pass through a straw.

The foods permitted are the same as those allowed on the full liquid diet. The advanced full liquid diet is made more nutritious by the addition of blended, thinned, and strained meat, potatoes, and vegetables. High-protein beverages are served with meals and between meals.

The standard menu mat provides approximately 4028 calories. The advanced full liquid diet meets the RDA for all nutrients tabulated.

Tonsillectomy and Adenoidectomy Cold Liquid Diet. This diet is used following a tonsillectomy and adenoidectomy (T&A). It is also used when only fluids or soothing foods in liquid form are tolerated.

The T&A cold liquid diet provides only cold liquids, which are free of irritants or acid properties. Foods allowed are flavored gelatins, ice cream, sherbet, and milk. A high protein beverage is served between meals.

The standard menu mat is DA Form 2902-14-R. The T&A cold liquid diet does not meet the RDA for niacin and Vitamin A for adult males or children ages 4 to 10, and is below the RDA for thiamine for children ages 1 to 4. It does not meet the RDA for iron for any age group.

Soft Diet. The soft diet is prescribed for patients unable to tolerate a regular diet. It is part of the progressive stages of diet therapy after surgery or during recovery from an acute illness.

The diet consists of solid foods that are prepared without added black pepper, chili powder, or chili pepper. It does not contain whole grain cereals or salads with raw, fresh fruits and vegetables. Serving sizes are small to provide a gradual increase in the amount of food from the liquid diet.

The standard menu mat (DA Form 2902-4-R) provides approximately 2236 calories. This diet does not meet the RDA in iron for females or thiamine for males, nor niacin for either males or females.

Dental Soft Diet. This diet is prescribed for patients who are recovering from extensive oral surgery, have severe gingivitis, have had multiple extractions, have chewing difficulties because of tooth loss or other oral condition, or for the very elderly, toothless patient.

The diet is composed of seasoned ground meats, vegetables, and other foods, which are easily chewed. The individuality of the patient must not be overlooked when a dental soft diet is prescribed. Many patients resent being served ground meat.

Standard menu mats available are DA Form 2902-6-R (dental soft diet) and DA Form 2906-13-R (dental soft, 2000 mg sodium diet). The dental soft diet does not meet the RDA in thiamin for males, nor iron for females.

Regular Diet. Regular diets are planned to meet the nutritional needs of adolescents, adults, and geriatric phases of the life span.

The regular diet includes the basic food groups and a variety of foods. The basic food groups include meat, milk, vegetables, fruits, bread and cereal, fats, and sweets.

The standard menu mat, DA Form 2901-R (Regular Diet) provides approximately 3375 calories. The selective menu is developed by each individual hospital according to patient needs, food availability, and cost. The regular diet is designed to provide exceptionally generous amounts of all recognized nutrients and meets or exceeds the RDA for all nutrients tabulated.

The Food Guide Pyramid is an outline of what we should eat each day (see figure 5-1).  Each of the food groups provides some of the nutrients you need. Food from one group cannot replace those of another group.

Figure 10-1. Food Guide Pyramid.

Diabetic Diet. The diabetic diet is indicated in the treatment of the metabolic disorder diabetes mellitus. This disease results from an inadequate production or utilization of insulin. The object of treating the diabetic patient by diet, with or without insulin or oral drugs, is to prevent hyperglycemia, hypoglycemia, glycosuria, and ketosis.

The diabetic food exchange lists are the basis for a meal planning system that was designed by a committee of the American Diabetes Association and The American Dietetic Association. The system lists: meat exchange, bread exchange, fruit and juice exchange, vegetable exchange, milk exchange and fat exchange. The number of exchanges allowed is based upon the doctor's order and the dietitian's calculations. Each diabetic diet should be individualized to meet the needs of the patient. The foods in each exchange contain the same amount of calories, carbohydrate, protein, and fat per portion size. Patients select from the exchange based upon their preference.

The adequacy and possible deficiencies depend on the calories. A diet of less than 1200 calories for women and less than 1500 calories for men would have a great chance of being deficient in some nutrients.

The goals of the diabetic diet are:

Liberal Bland Diet. This diet is indicated for any medical condition requiring treatment for the reduction of gastric secretion, such as gastric or duodenal ulcers, gastritis, esophagitis, or hiatal hernia.

The diet consists of any variety of regular foods and beverages, which are prepared or consumed without black pepper, chili powder, or chili pepper. Chocolate, coffee, tea, caffeine-containing products, and decaffeinated coffee are not included in the diet. The diet should be as liberal as possible and individualized to meet the needs of the patient. Foods, which cause the patient discomfort, should be avoided. Small, frequent feedings may be prescribed to lower the acidity of the gastric content and for the physical comfort of the patient.

The standard menu mat, DA Form 2902-1-R, provides 3213 calories. The liberal bland diet is slightly below the RDA for thiamine and niacin for men 19 to 22 years of age. It is also below the RDA in iron for women of all ages.

Low Fat Diet. Fat restricted diets may be indicated in diseases of the liver, gallbladder, or pancreas in which disturbances of the digestion and absorption of fat may occur (pancreatitis, post-gastrointestinal surgery, cholelithiasis, and cystic fibrosis).

The diet contains approximately 40 grams of fat from the six ounces of lean meat, fish, or poultry, one egg and three teaspoons of butter, margarine, or other allowed fats. Only lean, well-trimmed meats and skim milk are used. All foods are prepared without fat.

The standard menu mat, DA Form 2905-R, provides approximately 2168 calories. Caloric content of the diet can be increased by adding allowable breads, vegetables, fruits, or skim milk. The diet is below the RDA in iron for males between the ages of 11 and 22 and females 11 through 50 years of age.

Sodium Restricted Diet. The purpose of the sodium-restricted diet is to promote loss of body fluids for patients who are unable to excrete the element normally because of a pathological condition. The diet is indicated for the prevention, control, and elimination of edema in congestive heart failure; cirrhosis of the liver with ascites; renal disease complicated by either edema or hypertension; when administration of adrenocorticotrophic hormone (ACTH) or steroids are prescribed, and for certain endocrine disorders such as Cushing's disease and hypothyroidism.

The sodium-restricted diets provide a specific sodium level or a range of sodium. The diet order must indicate the specific sodium level or range desired either in milligrams (mg) or mill equivalent (mEq). Terms such as "salt free" and "low sodium" are not sufficient.

The diets are below the RDA in iron for males ages 11 to 22 and for females ages 11 to 50. Thiamine is inadequate for males at all levels. Calcium and niacin are also low for certain diets and ages.


As a nurse, your duties may include serving the diet trays at mealtime. For many patients, mealtime is the high point of the day. The patients are more apt to have a better appetite, eat more, and enjoy their food more if you prepare them for their meals before the trays arrive.

Avoid treatments such as enemas, dressings, and injections immediately before and after meals.


Helping patients meet their nutritional needs is a challenging task for a nurse. Ordering the tray and delivering it to the patient's bedside is not enough. You must see that he eats the food needed to meet his body requirements. Provide the patient with assistance to complete selective menus that meet his food preferences as much as possible. See to his comfort at mealtime. Without proper nutrition, the healing process slows down and the patient's condition does not improve as quickly as it should. You should always remember that the dietitians and hospital food service specialist (MOS 91M) of the hospital's Nutrition Care Division are available to you as experts in all aspects of patient nutrition care. Ask for their advice or intervention when you believe a patient's condition requires it.