There are different types of diet according to their texture, consistency and demand of the needed person. These are divided into two major categories.

Principles of diet

A well planned diet providing all the specific nutrients to the body helps to achieve nutritional homeostasis in a normal, healthy individual. However, in disease conditions, the body tissues either do not receive proper nutrients in sufficient amounts or cannot utilize the available nutrients owing to faulty digestion, absorption or transportation of food elements, thus affecting the nutritional homeostasis of the sick person. The diet therefore needs to be suitably modified. However, it is imperative that the basis for planning such modified diets should be the normal diet. Therefore diet therapy is concerned with the modification of normal diet to meet the requirements of the sick individual.

General objectives of diet therapy

  • To maintain a good nutritional status.
  • To correct nutrient deficiencies this may have occurred due to the disease.
  • To afford rest to the whole body or to the specific organ affected by the disease.
  • To adjust the food intake to the body's ability to metabolize the nutrients during the disease.
  • To bring about changes in body weight whenever necessary.

Advantages of using normal diet as the basis for therapeutic diets

  • It emphasizes the similarity of psychological and social needs of those who are well, even though there is quantitative and qualitative differences in requirements, thus ensuring better acceptability.
  • Food preparation is simplified when the modified diet is based upon the family pattern and the number of items requiring special preparation is reduced to a minimum.
  • The calculated values for the basic plan are useful in finding out the effects of addition or omission of certain foods. e.g.; if vegetables are restricted, vitamin A or Vitamin C deficiency can occur.

    Modified Diet

    A modified diet is any diet altered to include or exclude certain components, such as calories, fat, vitamins and minerals, according to “Nutrition Essentials for Nursing Practice” by Susan G. Dudek. Diets are typically modified for therapeutic reasons, including treatment of high blood pressure, low body weight or vitamin and mineral deficiencies. Talk to your physician about diet modifications that may help your condition, and follow up with a nutritionist to help you make the best dietary choices.

    Therapeutic Diet

    A therapeutic diet is a meal plan that controls the intake of certain foods. It’s a practice followed in many hospitals as part of the treatment of a medical condition and are normally prescribed by a physician and planned by a dietician. A therapeutic diet is usually a modification of a regular diet. Diets are modified for consistency, nutrition and new methods of making regular dishes.

    Mechanically altered diets

    This diet contain foods that are modified in texture. This include pureed diets include only pureed foods; mechanical soft diets may include solid foods that are mashed, minced, ground, or soft. Pureed diets are used for people with swallowing difficulty, poor lip and tongue control, or oral hypersensitivity. Mechanical soft diets are appropriate for people with limited chewing ability or certain swallowing impairments.

    Blenderized Liquid Diet

    This diet contains fluids and foods that are blenderized to liquid diet in liquid form. This is for people who cannot chew, swallow easily, or tolerate solid foods.

    Clear Liquid Diet

    This diet contains clear fluids or foods that are liquid at room preparation for temperature and leave minimal residue in the colon. This is for bowel surgery or colonoscopy, acute GI disturbances (such as after GI surgeries), or as a transition diet after intravenous feeding. This is for short-term use only.

    Liquid Diets

    Liquid diets consist of foods that are liquid at room temperature and are used in:

    • Febrile states (acute fever)
    • Post operative conditions

    Soft and Low Fiber Diets

     Soft diet is between liquid diet and normal diet. Soft diet includes both liquid and solid foods which contain restricted amount of indigestible carbohydrates and no tough connective tissue. The diet can be made soft by cooking, mashing, pureeing the foods used in a diet under normal conditions. One could also use of refined breads, cereals, vegetables and fruits. This diet is soft in texture and bland to taste

    Low Residue Diets

     The diet is made up of foods which can be completely absorbed, leaving little or no residue for feces formation. This diet is low in its mineral and vitamin content. Such diets need to be supplemented and foods high in fiber should be omitted. Two cups of milk may be permitted on a daily basis. Fruits and vegetables without skins are allowed. Meat should be tender or ground to reduce connective tissue. The diet is usually used in:

    • Severe diarrhea
    • Acute diverticulitis
    • Post operations

     High Fiber Diets

    Dietary fiber plays a significant role in colonic function. A high-fiber diet includes foods that have high fiber content. Fiber is essentially the outer crust of fruits, vegetables, and grains that is not broken down by the body. It helps in excretion of body wastes. It is also well known that fiber regulates the cholesterol levels. Oats, beans, peas, and certain fruits and vegetables (oranges, pears, Brussels sprouts, and carrots) are rich sources of fiber. This is recommended in case of constipation, or high cholesterol. This is a normal diet with fiber increased to 15–20 g daily.

    High Calorie Diets

     This is a normal diet with an increase in the calorie level to 3000 or more. If appetite is poor, small servings of highly reinforced foods are given. The diet may be modified in consistency and flavour, according to specific needs. Excessive amounts of foods that have a low calorific value and fried foods which disturb the appetite should be avoided. These diets are prescribed for

    • Weight loss
    • Fever
    • Hyperthyroidism
    • Burns

    Low Calorie Diet

     These diet controls calories, carbohydrates, proteins and fat intake in balanced amount to meet the nutritional needs and control blood sugar and weight. This is a normal diet with energy values reduced to 1500, 1200 or 1000 calories. Protein levels should be at 65 to 100 g. Supplements of Vitamin A and thiamine are usually required for diets below 1000 calories. These diets are prescribed for reducing body weight in

    • Diabetes Mellitus
    • Cardiovascular diseases
    • Hypertension
    • Gout
    • Gall bladder disease
    • Preceding surgery.

    High Protein Diet

     These are diets high in plant and animal proteins; used to treat malnutrition or to increase muscle mass. High protein diet of 100 – 125 g per day may be prescribed for a variety of conditions like

    • Fever
    • Hyperthyroidism
    • Burns
    • After surgery
    • Diarrhea
    • Elderly
    • Alcoholics

    Low Protein Diet

    A low-protein diet is a diet in which people reduce their intake of proteins. Such a diet is often prescribed to people with kidney or liver disorders. Low protein diets are usually prescribed for conditions like

    • Hepatic encephalopathy
    • Acute and chronic glomerulonephrites
    • Nephroslerosis
    • Acute and chronic renal failure
    • In-born errors of metabolism.

    In severe liver disorders, when protein cannot be synthesized, excess ammonia cannot be converted to urea for excretion and the patient develops hepatic coma. In this situation protein levels must be decreased or completely restricted for a few days. Patients with kidney require low protein diets since the kidney cannot excrete nitrogenous wastes. Diets containing 18 to 22 g of high biological value protein may be needed for the chronic uremic patients who are not being dialyzed. Low protein diets are also prescribed for patients with in-born errors of metabolism that result from lack of enzymes of the urea cycle.

     Fat Controlled Diet

     Fat controlled diets regulate the amount and type of fat allowed. The total calories from fats should give about 30% and 35% of the total calories with 10% from saturated fat and 12 – 14% from polyunsaturated fats. Even the intake of cholesterol also is reduced from the average daily intake of 600 to 300 mg usually fat controlled diets are prescribed for

    • Gall bladder diseases
    • Nontropical sprue
    • Celiac disease
    • Cystic fibrosis
    • Atherosclerosis
    • Myocardial infarction
    • Hyperlipidemia

    Low Sodium Diet

    The mineral content of the diet may also be modified. Four levels of sodium restriction are used 250, 500, 1000 and 2400 mgs. The diet excludes excess salty foods and salt in cooking and at the table. This diet is used both to prevent and treat edema. Therefore, it is prescribed for congestive heart failure, hypertension, liver and renal diseases. Then sodium must be added back by means of the diet.


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